FAQ
List,

I did not get a response to this question of mine. Meanwhile, I did a few tests and pestered Oracle Support to provide a definitive answer. The latter never happened. However, my tests did reveal a few things. Please read on if you are interested.

First, a standby database does not have to be in mounted state while being backed up by RMAN, contrary to what some notes in Metalink say. The standby could be any state - managed recovery or open read only, meaning it was in INCONSISTENT state. In that state, the restore simply needs more archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing special.

Second, only the archived logs of standby can be backed up, not the primary. While recovering the primary, you can simply use the archived logs from the standby, without any problems. Some documentation seems to indicate to the contrary.

In a restore situation you have the following choices.

If a datafile of primary is to be restored, merely ftp over the datafile from standby, rename it if necesary to the primary's name and recover that datafile.
If the standby datafile is gone, too; restore the RMAN backup of the datafile to the primary and recover it. Remember this backup was taken at the standby.
If archived logs are missing from primary, merely ftp over from the standby or restore directly to primary from backup.
If you primary is intact but the standby is broken, instead of restoring the standby datafile from tape, place the tablespace in hotbackup mode in primary and ftp the file over to the standby and perform a manual recovery. Then place the standby in managed recovery.

I hope this helps.

Arup Nanda
www.proligence.com

Original Message -----
To: ORACLE-L_at_fatcity.com
Sent: Thursday, May 08, 2003 11:15 PM

We run a standby database in managed recovery mode and back the standby using RMAN to save CPU cycles on primary. According to the fine manuals, the RMAN backup should be taken off standby after the managed recovery is canceled. Otherwise the backup is "inconsistent", although no further explanation is given what that means and whether that means an "invalid" backup. We currently cancel the managed recovery on standby and then initiate the RMAN backup. Has anyone done the backups without canceling managed recovery mode? I did a few test recoveries and every time the recovery was successful, but I will feel a lot reassured if I hear someone else has done that.

Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

Thanks a lot in advance.

Arup Nanda

--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Arup Nanda
INET: orarup_at_hotmail.com

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  • DENNIS WILLIAMS at May 14, 2003 at 7:57 pm
    Arup - Sorry you didn't get any replies earlier. The part that confuses me
    is what you are trying to accomplish. I've never done a standby database,
    only what I've heard in class. But my understanding is that there are many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.

    Dennis Williams
    DBA, 80%OCP, 100% DBA

    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L

    List,


    I did not get a response to this question of mine. Meanwhile, I did a few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read on if
    you are interested.


    First, a standby database does not have to be in mounted state while being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.


    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to the
    contrary.


    In a restore situation you have the following choices.


    If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover that
    datafile.
    If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken at
    the standby.
    If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.


    Arup Nanda
    www.proligence.com <http://www.proligence.com>


    Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear someone
    else has done that.


    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8


    Thanks a lot in advance.


    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------

    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • Arup Nanda at May 15, 2003 at 4:31 pm
    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.

    Arup

    Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM
    Arup - Sorry you didn't get any replies earlier. The part that confuses me
    is what you are trying to accomplish. I've never done a standby database,
    only what I've heard in class. But my understanding is that there are many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read on if
    you are interested.

    First, a standby database does not have to be in mounted state while being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Arup Nanda
    INET: orarup_at_hotmail.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • DENNIS WILLIAMS at May 16, 2003 at 12:22 am
    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA

    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L

    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.

    Arup

    Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM
    Arup - Sorry you didn't get any replies earlier. The part that confuses me
    is what you are trying to accomplish. I've never done a standby database,
    only what I've heard in class. But my understanding is that there are many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read on if
    you are interested.

    First, a standby database does not have to be in mounted state while being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Arup Nanda
    INET: orarup_at_hotmail.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • DENNIS WILLIAMS at May 16, 2003 at 4:21 pm
    List - Just wanted to report that off-list Arup straightened me out about
    why backing up the standby is a great idea and does not introduce any gaps
    in your recovery capability. He also reported that he has indeed tested
    recovery.

    Thanks Arup and if I get pushed toward standby databases, I'll know who
    to go to.
    Dennis Williams
    DBA, 80%OCP, 100% DBA

    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Thursday, May 15, 2003 6:24 PM
    To: 'ORACLE-L_at_fatcity.com'

    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA

    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L

    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.

    Arup

    Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM
    Arup - Sorry you didn't get any replies earlier. The part that confuses me
    is what you are trying to accomplish. I've never done a standby database,
    only what I've heard in class. But my understanding is that there are many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read on if
    you are interested.

    First, a standby database does not have to be in mounted state while being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Arup Nanda
    INET: orarup_at_hotmail.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • Arup Nanda at May 16, 2003 at 5:17 pm
    Dennis,

    Thanks for the update to the list.
    if I get pushed toward standby databases, I'll know who to go to. <<
    Oh.Oh!

    Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Friday, May 16, 2003 12:21 PM
    List - Just wanted to report that off-list Arup straightened me out about
    why backing up the standby is a great idea and does not introduce any gaps
    in your recovery capability. He also reported that he has indeed tested
    recovery.
    Thanks Arup and if I get pushed toward standby databases, I'll know who
    to go to.
    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 6:24 PM
    To: 'ORACLE-L_at_fatcity.com'


    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L


    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.
    Arup

    ----- Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM

    Arup - Sorry you didn't get any replies earlier. The part that confuses
    me
    is what you are trying to accomplish. I've never done a standby
    database,
    only what I've heard in class. But my understanding is that there are
    many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a
    few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read
    on
    if
    you are interested.

    First, a standby database does not have to be in mounted state while
    being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was
    in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to
    the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover
    that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken
    at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode
    in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear
    someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Arup Nanda
    INET: orarup_at_hotmail.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Arup Nanda
    INET: orarup_at_hotmail.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
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    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
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    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • Tim Gorman at May 16, 2003 at 5:53 pm
    Hopefully the FORCE LOGGING capabilities of 9i were considered in that
    discussion. It's a wonderful thing -- DBAs get reliable and complete
    standby propagation and developers/end-users get to think that they are
    optimizing performance using NOLOGGING... :-)

    It isn't everyday that you can make everyone happy!
    on 5/16/03 9:21 AM, DENNIS WILLIAMS at DWILLIAMS_at_LIFETOUCH.COM wrote:

    List - Just wanted to report that off-list Arup straightened me out about
    why backing up the standby is a great idea and does not introduce any gaps
    in your recovery capability. He also reported that he has indeed tested
    recovery.
    Thanks Arup and if I get pushed toward standby databases, I'll know who
    to go to.
    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 6:24 PM
    To: 'ORACLE-L_at_fatcity.com'


    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L


    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.

    Arup

    ----- Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM

    Arup - Sorry you didn't get any replies earlier. The part that confuses me
    is what you are trying to accomplish. I've never done a standby database,
    only what I've heard in class. But my understanding is that there are many
    actions you can take against the primary database that will render the
    standby unusable. Therefore, the usual issue isn't "how to back up the
    standby". It is only a copy of the primary, so most people are much more
    concerned about the primary and consider the standby a "throwaway" since it
    is just a copy of the primary. The usual issue is how to quickly rebuild the
    standby database. I believe that RMAN can help with that because, as you
    point out, it is good at performing online backups. Robert Freeman has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please read on if
    you are interested.

    First, a standby database does not have to be in mounted state while being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs from the
    standby, without any problems. Some documentation seems to indicate to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of the
    datafile to the primary and recover it. Remember this backup was taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the standby
    using RMAN to save CPU cycles on primary. According to the fine manuals, the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris 2.8

    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Tim Gorman
    INET: tim_at_sagelogix.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
  • Freeman Robert - IL at May 16, 2003 at 9:07 pm
    A most excellent point, and great new feature in 9i.
    Just wait until you see what's coming folks!!

    RF

    -----Original Message-----
    To: Multiple recipients of list ORACLE-L
    Sent: 5/16/2003 12:53 PM

    Hopefully the FORCE LOGGING capabilities of 9i were considered in that
    discussion. It's a wonderful thing -- DBAs get reliable and complete
    standby propagation and developers/end-users get to think that they are
    optimizing performance using NOLOGGING... :-)

    It isn't everyday that you can make everyone happy!
    on 5/16/03 9:21 AM, DENNIS WILLIAMS at DWILLIAMS_at_LIFETOUCH.COM wrote:

    List - Just wanted to report that off-list Arup straightened me out about
    why backing up the standby is a great idea and does not introduce any gaps
    in your recovery capability. He also reported that he has indeed tested
    recovery.
    Thanks Arup and if I get pushed toward standby databases, I'll know who
    to go to.
    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 6:24 PM
    To: 'ORACLE-L_at_fatcity.com'


    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the
    answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L


    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be
    difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but
    rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.

    Arup

    ----- Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM

    Arup - Sorry you didn't get any replies earlier. The part that
    confuses me
    is what you are trying to accomplish. I've never done a standby
    database,
    only what I've heard in class. But my understanding is that there are
    many
    actions you can take against the primary database that will render
    the
    standby unusable. Therefore, the usual issue isn't "how to back up
    the
    standby". It is only a copy of the primary, so most people are much
    more
    concerned about the primary and consider the standby a "throwaway"
    since
    it
    is just a copy of the primary. The usual issue is how to quickly
    rebuild
    the
    standby database. I believe that RMAN can help with that because, as
    you
    point out, it is good at performing online backups. Robert Freeman
    has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a
    few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please
    read on
    if
    you are interested.

    First, a standby database does not have to be in mounted state while
    being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it
    was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs
    from
    the
    standby, without any problems. Some documentation seems to indicate
    to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover
    that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of
    the
    datafile to the primary and recover it. Remember this backup was
    taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from
    the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup
    mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the
    standby
    using RMAN to save CPU cycles on primary. According to the fine
    manuals,
    the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an
    "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without
    canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear
    someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris
    2.8
    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM
    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
    the message BODY, include a line containing: UNSUB ORACLE-L
    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Tim Gorman
    INET: tim_at_sagelogix.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
    ---------------------------------------------------------------------
    To REMOVE yourself from this mailing list, send an E-Mail message
    to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
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    (or the name of mailing list you want to be removed from). You may
    also send the HELP command for other information (like subscribing).
    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: Freeman Robert - IL
    INET: FREEMANR_at_tusc.com

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
    San Diego, California -- Mailing list and web hosting services
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  • Pete Sharman at May 16, 2003 at 9:36 pm
    Tell them and you die! :)

    Pete
    "Controlling developers is like herding cats."
    Kevin Loney, Oracle DBA Handbook
    "Oh no, it's not. It's much harder than that!"
    Bruce Pihlamae, long-term Oracle DBA


    -----Original Message-----
    - IL
    Sent: Friday, May 16, 2003 2:07 PM
    To: Multiple recipients of list ORACLE-L

    A most excellent point, and great new feature in 9i.
    Just wait until you see what's coming folks!!

    RF

    -----Original Message-----
    To: Multiple recipients of list ORACLE-L
    Sent: 5/16/2003 12:53 PM

    Hopefully the FORCE LOGGING capabilities of 9i were considered in that
    discussion. It's a wonderful thing -- DBAs get reliable and complete
    standby propagation and developers/end-users get to think that they are
    optimizing performance using NOLOGGING... :-)

    It isn't everyday that you can make everyone happy!
    on 5/16/03 9:21 AM, DENNIS WILLIAMS at DWILLIAMS_at_LIFETOUCH.COM wrote:

    List - Just wanted to report that off-list Arup straightened me out about
    why backing up the standby is a great idea and does not introduce any gaps
    in your recovery capability. He also reported that he has indeed tested
    recovery.
    Thanks Arup and if I get pushed toward standby databases, I'll know who
    to go to.
    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 6:24 PM
    To: 'ORACLE-L_at_fatcity.com'


    Arup - Thanks for clarifying that. Just the thought of "we can't tax the
    production server with backups, so we'll backup the standby instead" gives
    me the willies. But you know your environment. Regardless of the
    answer you
    get from the manuals on this issue, I would test it. Verify whether you can
    recover from the backup.

    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com


    -----Original Message-----
    Sent: Thursday, May 15, 2003 11:32 AM
    To: Multiple recipients of list ORACLE-L


    Dennis,

    Absolutely not! Standby databases are not for throw-away. Since they run on
    a different server, they RMAN backups from that server will reduce the load
    on the primary server significantly. Also if your tape backup software
    (Tivoli in my case) uses compression, precious CPU cycles are saved from the
    primary. So, it's an important part of your overall infrastructure strategy
    and thus backups from standbny are necessary, not just desirable. Of course,
    if your standby amounts to, say, 10% of your primary, it may be
    difficult to
    run RMAN and tape compression over there.

    The issue was not how to take backups from standby database, but
    rather the
    confusion created by Notes and Manuals stating that "standby should NOT be
    in managed recovery mode while being backed up". This means for the duration
    of the backup, which in our case takes 6 hours (2.3 TB, OLTP, 1000
    concurrent sessions), the standby is out of sync with the primary. My
    question was wheether we could backup WHILE in managed recovery mode. And,
    fortunately, the answer is yes.

    I have been doing standby databases for years, but the backups were always
    from the primary, so this issue never really arose. At this customer, the
    size of the database, time of backup and insfrastructure prompted me to
    rethink that approach.

    HTH.
    Arup

    ----- Original Message -----
    To: "Multiple recipients of list ORACLE-L"
    Sent: Wednesday, May 14, 2003 3:57 PM

    Arup - Sorry you didn't get any replies earlier. The part that
    confuses me
    is what you are trying to accomplish. I've never done a standby
    database,
    only what I've heard in class. But my understanding is that there are
    many
    actions you can take against the primary database that will render
    the
    standby unusable. Therefore, the usual issue isn't "how to back up
    the
    standby". It is only a copy of the primary, so most people are much
    more
    concerned about the primary and consider the standby a "throwaway"
    since
    it
    is just a copy of the primary. The usual issue is how to quickly
    rebuild
    the
    standby database. I believe that RMAN can help with that because, as
    you
    point out, it is good at performing online backups. Robert Freeman
    has a
    chapter on how to do that in his book.



    Dennis Williams
    DBA, 80%OCP, 100% DBA
    Lifetouch, Inc.
    dwilliams_at_lifetouch.com

    -----Original Message-----
    Sent: Wednesday, May 14, 2003 11:22 AM
    To: Multiple recipients of list ORACLE-L


    List,

    I did not get a response to this question of mine. Meanwhile, I did a
    few
    tests and pestered Oracle Support to provide a definitive answer. The latter
    never happened. However, my tests did reveal a few things. Please
    read on
    if
    you are interested.

    First, a standby database does not have to be in mounted state while
    being
    backed up by RMAN, contrary to what some notes in Metalink say. The standby
    could be any state - managed recovery or open read only, meaning it
    was in
    INCONSISTENT state. In that state, the restore simply needs more
    archivedlogs to be conistent, just like a simple RMAN or hot backup, nothing
    special.

    Second, only the archived logs of standby can be backed up, not the primary.
    While recovering the primary, you can simply use the archived logs
    from
    the
    standby, without any problems. Some documentation seems to indicate
    to the
    contrary.

    In a restore situation you have the following choices.

    1. If a datafile of primary is to be restored, merely ftp over the datafile
    from standby, rename it if necesary to the primary's name and recover
    that
    datafile.
    2. If the standby datafile is gone, too; restore the RMAN backup of
    the
    datafile to the primary and recover it. Remember this backup was
    taken at
    the standby.
    3. If archived logs are missing from primary, merely ftp over from
    the
    standby or restore directly to primary from backup.
    4. If you primary is intact but the standby is broken, instead of restoring
    the standby datafile from tape, place the tablespace in hotbackup
    mode in
    primary and ftp the file over to the standby and perform a manual recovery.
    Then place the standby in managed recovery.

    I hope this helps.

    Arup Nanda
    www.proligence.com <http://www.proligence.com>

    ----- Original Message -----
    To: ORACLE-L_at_fatcity.com
    Sent: Thursday, May 08, 2003 11:15 PM

    We run a standby database in managed recovery mode and back the
    standby
    using RMAN to save CPU cycles on primary. According to the fine
    manuals,
    the
    RMAN backup should be taken off standby after the managed recovery is
    canceled. Otherwise the backup is "inconsistent", although no further
    explanation is given what that means and whether that means an
    "invalid"
    backup. We currently cancel the managed recovery on standby and then
    initiate the RMAN backup. Has anyone done the backups without
    canceling
    managed recovery mode? I did a few test recoveries and every time the
    recovery was successful, but I will feel a lot reassured if I hear
    someone
    else has done that.

    Oracle 8.1.7.4, RMAN Catalog 8.1.7.4, RMAN version 8.1.7.4, Solaris
    2.8
    Thanks a lot in advance.

    Arup Nanda

    --
    Please see the official ORACLE-L FAQ: http://www.orafaq.net
    --
    Author: DENNIS WILLIAMS
    INET: DWILLIAMS_at_LIFETOUCH.COM

    Fat City Network Services -- 858-538-5051 http://www.fatcity.com
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    Author: Freeman Robert - IL
    INET: FREEMANR_at_tusc.com

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    --
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    Author: Pete Sharman
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