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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
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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