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Date: Thu, 22 Nov 2012 12:33:37 -0500
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Subject: Re: CheckPoint Node
From: Jean-Marc Spaggiari <jean-marc@spaggiari.org>
To: user@hadoop.apache.org
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Hi Harsh,

Thanks for pointing me to this link. I will take a close look at it.

So with 1.x and 0.23.x, what's the impact on the data if the namenode
server hard-drive die? Is there any critical data stored locally? Or I
simply need to build a new namenode, start it and restart all my
namenodes to find my data back?

I can deal with my application not beeing available, but loosing data
can be a bigger issue.

Thanks,

JM

2012/11/22, Harsh J <harsh@cloudera.com>:
> Hey Jean,
>
> The 1.x, 0.23.x release lines both don't have NameNode HA features.
> The current 2.x releases carry HA-NN abilities, and this is documented
> at
> http://hadoop.apache.org/docs/current/hadoop-yarn/hadoop-yarn-site/HDFSHighAvailability.html.
>
> On Thu, Nov 22, 2012 at 10:18 PM, Jean-Marc Spaggiari
> <jean-marc@spaggiari.org> wrote:
>> Replying to myself ;)
>>
>> By digging a bit more I figured that 1.0 version is older than 0.23.4
>> version and that backupnodes are on 0.23.4. Secondarynamenodes on 1.0
>> are now deprecated.
>>
>> I'm still a bit mixed up on the way to achieve HA for the namenode
>> (1.0 or 0.23.4) but I will continue to dig over internet.
>>
>> JM
>>
>> 2012/11/22, Jean-Marc Spaggiari <jean-marc@spaggiari.org>:
>>> Hi,
>>>
>>> I'm reading a bit about hadoop and I'm trying to increase the HA of my
>>> current cluster.
>>>
>>> Today I have 8 datanodes and one namenode.
>>>
>>> By reading here: http://www.aosabook.org/en/hdfs.html I can see that a
>>> Checkpoint node might be a good idea.
>>>
>>> So I'm trying to start a checkpoint node. I looked at the hadoop
>>> online doc. There is a link toe describe the command usage "For
>>> command usage, see namenode." but this link is not working. Also, if I
>>> try hadoop-deamon.sh start namenode -checkpoint as discribed in the
>>> documentation, it's not starting.
>>>
>>> So I'n wondering, is there anywhere where I can find up to date
>>> documentation about the checkpoint node? I will most probably try the
>>> BackupNode.
>>>
>>> I'm using hadoop 1.0.3. The options I have to start on this version
>>> are namenode, secondarynamenode, datanode, dfsadmin, mradmin, fsck and
>>> fs. Should I start some secondarynamenodes instead of backupnode and
>>> checkpointnode?
>>>
>>> Thanks,
>>>
>>> JM
>>>
>
>
>
> --
> Harsh J
>