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HBase, mail # user - region server down when scanning using mapreduce


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Re: region server down when scanning using mapreduce
Azuryy Yu 2013-03-12, 05:41
please read here http://hbase.apache.org/book.html (11.8.5. Block Cache) to
get some background of block cache.
On Tue, Mar 12, 2013 at 1:31 PM, Lu, Wei <[EMAIL PROTECTED]> wrote:

> No, does block cache matter? Btw, the mr dump is a mr program we
> implemented rather than the hbase tool.
>
> Thanks
>
> -----Original Message-----
> From: Azuryy Yu [mailto:[EMAIL PROTECTED]]
> Sent: Tuesday, March 12, 2013 1:18 PM
> To: [EMAIL PROTECTED]
> Subject: Re: region server down when scanning using mapreduce
>
> did you closed block cache when you used mr dump?
> On Mar 12, 2013 1:06 PM, "Lu, Wei" <[EMAIL PROTECTED]> wrote:
>
> > Hi,
> >
> > When we use mapreduce to dump data from a pretty large table on hbase.
> One
> > region server crash and then another. Mapreduce is deployed together with
> > hbase.
> >
> > 1) From log of the region server, there are both "next" and "multi"
> > operations on going. Is it because there is write/read conflict that
> cause
> > scanner timeout?
> > 2) Region server has 24 cores, and # max map tasks is 24 too; the table
> > has about 30 regions (each of size 0.5G) on the region server, is it
> > because cpu is all used by mapreduce and that case region server slow and
> > then timeout?
> > 2) current hbase.regionserver.handler.count is 10 by default, should it
> be
> > enlarged?
> >
> > Please give us some advices.
> >
> > Thanks,
> > Wei
> >
> >
> > Log information:
> >
> >
> > [Regionserver rs21:]
> >
> > 2013-03-11 18:36:28,148 INFO
> > org.apache.hadoop.hbase.regionserver.wal.HLog: Roll /hbase/.logs/
> > adcbg21.machine.wisdom.com
> ,60020,1363010589837/rs21%2C60020%2C1363010589837.1363025554488,
> > entries=22417, filesize=127539793.  for
> >
> /hbase/.logs/rs21,60020,1363010589837/rs21%2C60020%2C1363010589837.1363026988052
> > 2013-03-11 18:37:39,481 WARN org.apache.hadoop.hbase.util.Sleeper: We
> > slept 28183ms instead of 3000ms, this is likely due to a long garbage
> > collecting pause and it's usually bad, see
> > http://hbase.apache.org/book.html#trouble.rs.runtime.zkexpired
> > 2013-03-11 18:37:40,163 WARN org.apache.hadoop.ipc.HBaseServer:
> > (responseTooSlow):
> > {"processingtimems":29830,"call":"next(1656517918313948447, 1000), rpc
> > version=1, client version=29, methodsFingerPrint=54742778","client":"
> > 10.20.127.21:56058
> >
> ","starttimems":1363027030280,"queuetimems":4602,"class":"HRegionServer","responsesize":2774484,"method":"next"}
> > 2013-03-11 18:37:40,163 WARN org.apache.hadoop.ipc.HBaseServer:
> > (responseTooSlow):
> > {"processingtimems":31195,"call":"next(-8353194140406556404, 1000), rpc
> > version=1, client version=29, methodsFingerPrint=54742778","client":"
> > 10.20.127.21:56529
> >
> ","starttimems":1363027028804,"queuetimems":3634,"class":"HRegionServer","responsesize":2270919,"method":"next"}
> > 2013-03-11 18:37:40,163 WARN org.apache.hadoop.ipc.HBaseServer:
> > (responseTooSlow):
> > {"processingtimems":30965,"call":"next(2623756537510669130, 1000), rpc
> > version=1, client version=29, methodsFingerPrint=54742778","client":"
> > 10.20.127.21:56146
> >
> ","starttimems":1363027028807,"queuetimems":3484,"class":"HRegionServer","responsesize":2753299,"method":"next"}
> > 2013-03-11 18:37:40,236 WARN org.apache.hadoop.ipc.HBaseServer:
> > (responseTooSlow):
> > {"processingtimems":31023,"call":"next(5293572780165196795, 1000), rpc
> > version=1, client version=29, methodsFingerPrint=54742778","client":"
> > 10.20.127.21:56069
> >
> ","starttimems":1363027029086,"queuetimems":3589,"class":"HRegionServer","responsesize":2722543,"method":"next"}
> > 2013-03-11 18:37:40,368 WARN org.apache.hadoop.ipc.HBaseServer:
> > (responseTooSlow):
> > {"processingtimems":31160,"call":"next(-4285417329791344278, 1000), rpc
> > version=1, client version=29, methodsFingerPrint=54742778","client":"
> > 10.20.127.21:56586
> >
> ","starttimems":1363027029204,"queuetimems":3707,"class":"HRegionServer","responsesize":2938870,"method":"next"}
> > 2013-03-11 18:37:43,652 WARN org.apache.hadoop.ipc.HBaseServer: