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From Arpit Agarwal <aagar...@hortonworks.com>
Subject Re: how to reduce delay in HDFS restart
Date Thu, 24 Jul 2014 18:31:20 GMT
Which version of Hadoop?

Yes saveNamespace as you described will checkpoint the FsImage and reset
your edits log so it will reduce startup time.

On Thu, Jul 24, 2014 at 8:25 AM, Anfernee Xu <anfernee.xu@gmail.com> wrote:

> Yes, I have secondary NM, but without HA, but after I killed NM and
> secondary NM, the startup time was still too long(4 hours), what else
> should I do?  Will "hadoop dfsadmin -saveNamespace" resolve the issue?
> Thanks for your help.
> On Wed, Jul 23, 2014 at 10:58 PM, Stanley Shi <sshi@gopivotal.com> wrote:
>> Do you have a secondary namenode running? Secondary NN is used for this
>> purpose;
>> Also, if you have HDFS HA enabled, this problem will also not occur.
>> Regards,
>> *Stanley Shi,*
>> On Tue, Jul 22, 2014 at 7:24 AM, Anfernee Xu <anfernee.xu@gmail.com>
>> wrote:
>>> Hi,
>>> For some reason, all PIDs file are missing in my cluster, I have to
>>> manually kill all java processes on all machines, then I restarted the
>>> HDFS, but it took so long time in applying changes in edit log file, so my
>>> question is how can I reduce the delay? My understanding is as follows,
>>> could someone please give some comments on it?
>>>     hadoop dfsadmin -safemode enter
>>>     #save current in-mem data to image file and reset edit log
>>>     hadoop dfsadmin -saveNamespace
>>> --
>>> --Anfernee
> --
> --Anfernee

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