FAQ
What is the implication of manually forcing name node to leave safemode?

What properties do HDFS lose by doing that?

One gain to that is that the file system will be available for writes
immediately.


Cagdas

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Best Regards, Cagdas Evren Gerede
Home Page: http://cagdasgerede.info

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  • Ted Dunning at May 15, 2008 at 1:21 am
    That really depends on why the name node is in safemode.

    If the reason is system startup in which only a few datanodes have reported
    in, then the only problem is that some files may not be fully present.

    If the reason is some sort of system corruption, it could be a really big
    mistake to force the system out of safe mode, mostly likely because you are
    forcing the system out in order to cause more damage.



    On 5/14/08 5:54 PM, "Cagdas Gerede" wrote:

    What is the implication of manually forcing name node to leave safemode?

    What properties do HDFS lose by doing that?

    One gain to that is that the file system will be available for writes
    immediately.


    Cagdas
  • Cagdas Gerede at May 15, 2008 at 7:25 am
    What are the cases that a system can go into safemode?
    1) When master starts.
    2) ?

    What are the actions that are being carried out during safemode?
    1) Wait for block reports, Process block reports, Construct the blockmap in
    memory.
    2) ?

    Cagdas
    On Thu, May 15, 2008 at 4:20 AM, Ted Dunning wrote:


    That really depends on why the name node is in safemode.

    If the reason is system startup in which only a few datanodes have reported
    in, then the only problem is that some files may not be fully present.

    If the reason is some sort of system corruption, it could be a really big
    mistake to force the system out of safe mode, mostly likely because you are
    forcing the system out in order to cause more damage.



    On 5/14/08 5:54 PM, "Cagdas Gerede" wrote:

    What is the implication of manually forcing name node to leave safemode?

    What properties do HDFS lose by doing that?

    One gain to that is that the file system will be available for writes
    immediately.


    Cagdas

    --
    ------------
    Best Regards, Cagdas Evren Gerede
    Home Page: http://cagdasgerede.info

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postedMay 15, '08 at 12:55a
activeMay 15, '08 at 7:25a
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