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MapReduce >> mail # user >> why multiple checkpoint nodes?


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Re: why multiple checkpoint nodes?
It would be important to point the document (which I believe is
http://hadoop.apache.org/docs/stable/hdfs_user_guide.html) and the version
of Hadoop you are interested in. At one time, the documentation was
misleading. The 1.x version didn't have checkpoint/backup nodes only the
secondary namenode. I don't believe it has changed but I might be wrong (or
the documentation still hasn't been fixed). The 2.x version will have
namenode HA which will be the final solution.

Regards

Bertrand
On Thu, Apr 18, 2013 at 7:20 PM, Thanh Do <[EMAIL PROTECTED]> wrote:

> so reliability (to prevent metadata loss) is the main motivation for
> multiple checkpoint nodes?
>
> Does anybody use multiple checkpoint nodes in real life?
>
> Thanks
>
>
> On Thu, Apr 18, 2013 at 12:07 PM, shashwat shriparv <
> [EMAIL PROTECTED]> wrote:
>
>> more checkpoint nodes means more backup of the metadata :)
>>
>> *Thanks & Regards    *
>>
>> ∞
>> Shashwat Shriparv
>>
>>
>>
>> On Thu, Apr 18, 2013 at 9:35 PM, Thanh Do <[EMAIL PROTECTED]> wrote:
>>
>>> Hi all,
>>>
>>> The document says "Multiple checkpoint nodes may be specified in the
>>> cluster configuration file".
>>>
>>> Can some one clarify me that why we really need to run multiple
>>> checkpoint nodes anyway? Is it possible that while checkpoint node A is
>>> doing checkpoint, and check point node B kicks in and does another
>>> checkpoint?
>>>
>>> Thanks,
>>> Thanh
>>>
>>
>>
>
--
Bertrand Dechoux
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB