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Re: CheckPoint Node
Hi JM,

If you migrate 1.0.3 to 2.0.x, could you mind to share your migration steps? it is because I also have a 1.0.4 cluster (Ubuntu 12.04, Hadoop 1.0.4, Hbase 0.94.2 and ZooKeeper 3.4.4 ) and want to migrate it to 2.0.x in order to avoid the hardware failure of the NameNode.

I have a testing cluster ready for the migration test.

On 1 Dec 2012, at 10:25 AM, Jean-Marc Spaggiari wrote:

> Sorry about that. My fault.
> I have put this on the core-site.xml file but should be on the hdfs-site.xml...
> I moved it and it's now working fine.
> Thanks.
> JM
> 2012/11/30, Jean-Marc Spaggiari <[EMAIL PROTECTED]>:
>> Hi,
>> Is there a way to ask Hadoop to display its parameters?
>> I have updated the property as followed:
>>  <property>
>>    <name>dfs.name.dir</name>
>>    <value>${hadoop.tmp.dir}/dfs/name,/media/usb0/</value>
>>  </property>
>> But even if I stop/start hadoop, there is nothing written on the usb
>> drive. So I'm wondering if there is a command line like bin/hadoop
>> --showparameters
>> Thanks,
>> JM
>> 2012/11/22, Jean-Marc Spaggiari <[EMAIL PROTECTED]>:
>>> Perfect. Thanks again for your time!
>>> I will first add another drive on the Namenode because this will take
>>> 5 minutes. Then I will read about the migration from 1.0.3 to 2.0.x
>>> and most probably will use the zookeeper solution.
>>> This will take more time, so will be done over the week-end.
>>> I lost 2 hard drives this week (2 datanodes), so I'm not a bit
>>> concerned about the NameNode data. Just want to secure that a bit
>>> more.
>>> JM
>>> 2012/11/22, Harsh J <[EMAIL PROTECTED]>:
>>>> Jean-Marc (Sorry if I've been spelling your name wrong),
>>>> 0.94 does support Hadoop-2 already, and works pretty well with it, if
>>>> that is your only concern. You only need to use the right download (or
>>>> if you compile, use the -Dhadoop.profile=23 maven option).
>>>> You will need to restart the NameNode to make changes to the
>>>> dfs.name.dir property and set it into effect. A reasonably fast disk
>>>> is needed for quicker edit log writes (few bytes worth in each round)
>>>> but a large, or SSD-style disk is not a requisite. An external disk
>>>> would work fine too (instead of an NFS), as long as it is reliable.
>>>> You do not need to copy data manually - just ensure that your NameNode
>>>> process user owns the directory and it will auto-populate the empty
>>>> directory on startup.
>>>> Operationally speaking, in case 1/2 disk fails, the NN Web UI (and
>>>> metrics as well) will indicate this (see bottom of NN UI page for an
>>>> example of what am talking about) but the NN will continue to run with
>>>> the lone remaining disk, but its not a good idea to let it run for too
>>>> long without fixing/replacing the disk, for you will be losing out on
>>>> redundancy.
>>>> On Thu, Nov 22, 2012 at 11:59 PM, Jean-Marc Spaggiari
>>>> <[EMAIL PROTECTED]> wrote:
>>>>> Hi Harsh,
>>>>> Again, thanks a lot for all those details.
>>>>> I read the previous link and I totally understand the HA NameNode. I
>>>>> already have a zookeeper quorum (3 servers) that I will be able to
>>>>> re-use. However, I'm running HBase 0.94.2 which is not yet compatible
>>>>> (I think) with Hadoop 2.0.x. So I will have to go with a non-HA
>>>>> NameNode until I can migrate to a stable 0.96 HBase version.
>>>>> Can I "simply" add one directory to dfs.name.dir and restart
>>>>> my namenode? Is it going to feed all the required information in this
>>>>> directory? Or do I need to copy the data of the existing one in the
>>>>> new one before I restart it? Also, does it need a fast transfert rate?
>>>>> Or will an exteral hard drive (quick to be moved to another server if
>>>>> required) be enought?
>>>>> 2012/11/22, Harsh J <[EMAIL PROTECTED]>:
>>>>>> Please follow the tips provided at
>>>>>> http://wiki.apache.org/hadoop/FAQ#How_do_I_set_up_a_hadoop_node_to_use_multiple_volumes.3Fand