FAQ
As far as my understanding goes, I feel that Backup node is much more
efficient then the Checkpoint node, as it has the current(up-to-date) copy
of file system too.
I do not understand what would be the use case (in a production environment)
tin which someone would prefer Checkpoint node over Backup node, or I should
ask, what do people generally prefer of the two and why ?

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  • Todd Lipcon at May 25, 2011 at 1:13 am
    Hi Sulabh,

    Neither of these nodes have been "productionized" -- so I don't think
    anyone would have a good answer for you about what works in
    production. They are only available in 0.21 and haven't had any
    substantial QA.

    One of the potential issues with the BN is that it can delay the
    logging of edits by the primary NN, if the BN were to hang or go
    offline. The CN would not have such an issue.

    -Todd
    On Tue, May 24, 2011 at 5:08 PM, sulabh choudhury wrote:
    As far as my understanding goes, I feel that Backup node is much more
    efficient then the Checkpoint node, as it has the current(up-to-date) copy
    of file system too.
    I do not understand what would be the use case (in a production environment)
    tin which someone would prefer Checkpoint node over Backup node, or I should
    ask, what do people generally prefer of the two and why ?


    --
    Todd Lipcon
    Software Engineer, Cloudera
  • Sulabh choudhury at May 25, 2011 at 8:51 pm
    Thanks for the response.
    Well the hanging of BN and its consequences seem to be a scary situation.
    So when using a CN, in case of a NN failure...we would loose the edits after
    the last checkpoint, but it seems to be a decent trade-off for the stability
    which the Backup Node might lack.

    On Tue, May 24, 2011 at 6:12 PM, Todd Lipcon wrote:

    Hi Sulabh,

    Neither of these nodes have been "productionized" -- so I don't think
    anyone would have a good answer for you about what works in
    production. They are only available in 0.21 and haven't had any
    substantial QA.

    One of the potential issues with the BN is that it can delay the
    logging of edits by the primary NN, if the BN were to hang or go
    offline. The CN would not have such an issue.

    -Todd
    On Tue, May 24, 2011 at 5:08 PM, sulabh choudhury wrote:
    As far as my understanding goes, I feel that Backup node is much more
    efficient then the Checkpoint node, as it has the current(up-to-date) copy
    of file system too.
    I do not understand what would be the use case (in a production
    environment)
    tin which someone would prefer Checkpoint node over Backup node, or I should
    ask, what do people generally prefer of the two and why ?


    --
    Todd Lipcon
    Software Engineer, Cloudera

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postedMay 25, '11 at 12:09a
activeMay 25, '11 at 8:51p
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