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From jlei liu <liulei...@gmail.com>
Subject Re: support checksums in HBase block
Date Sun, 16 Sep 2012 02:06:35 GMT
The HBase support checksums in HBase block cache in
HBASE-5074<https://issues.apache.org/jira/browse/HBASE-5074>
jira.
The  HBase  support checksums for decrease the iops of  HDFS, so that HDFS
dont't need to read the metadata of block file. But in hadoop-0.20.2-cdh3u5
version, BlockSender still read the metadata file even if the
hbase.regionserver.checksum.verify property is ture. Because the HBASE-5074
jira can't decrease the iops of HDFS, so I want to set
hbase.regionserver.checksum.verify property to fasle.
2012/9/16 Stack <stack@duboce.net>

> On Sat, Sep 15, 2012 at 10:31 AM, jlei liu <liulei412@gmail.com> wrote:
> > I use Hbase0.94.1 and  hadoop-0.20.2-cdh3u5.
> >
> > The Hbase0.94.1 write checksums in HBase block, so we don't need to read
> > checksums from metadata file of block file. But I find the BlockSender
> > still read checksums from metadata file of block file every time,
>
> How are you figuring this?   That sounds like a regression.
>
> In 0.94.x the default is that hbase.regionserver.checksum.verify is
> true which should have hbase doing checksum verify on read rather than
> hdfs.
>
> >  so the
> > Hbase0.94.1 can't decrease the iops, that is right? If that is right,
> > should I set the  hbase.regionserver.checksum.verify property to false in
> > order to  avoid the Hbase0.94.1 to verify th checksum?
> >
>
> It would be interesting flipping the switch.  If things went faster,
> then for sure there is a regression.
> St.Ack
>

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