Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
MapReduce, mail # user - why multiple checkpoint nodes?


Copy link to this message
-
Re: why multiple checkpoint nodes?
Thanh Do 2013-04-19, 02:54
Thanks guys for updating!

Yeah, I read the thread that Checkpoint/BackupNode may be get deprecated.
SNN is a way to go then.

I just wonder if we use multiple CheckpointNodes, we might run into the
situation where while a checkpoint is on-going, but the first
CheckpointNode is slow, then the second checkpointNode kicks in, just
wonder what would happen.
On Thu, Apr 18, 2013 at 3:07 PM, Mohammad Tariq <[EMAIL PROTECTED]> wrote:

> Hello Thanh,
>
>        Just to keep you updated, checkpoint node might get depricated. So,
> it's always better to use secondary namenode. More on this could be found
> here :
> https://issues.apache.org/jira/browse/HDFS-2397
> https://issues.apache.org/jira/browse/HDFS-4114
>
> Warm Regards,
> Tariq
> https://mtariq.jux.com/
> cloudfront.blogspot.com
>
>
> On Fri, Apr 19, 2013 at 1:15 AM, Bertrand Dechoux <[EMAIL PROTECTED]>wrote:
>
>> 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
>>
>
>