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From "Slava Gorelik" <slava.gore...@gmail.com>
Subject Re: Hbase / Hadoop Tuning
Date Thu, 02 Oct 2008 20:12:23 GMT
Thank You.
According to doing write in MR jobs, the problem is that rows are coming to
webapp one by one and i can't accumulate them into
one big batch update, it means i need to run MR job for each single row, in
this case will MR jobs help ?

Best Regards.

On Thu, Oct 2, 2008 at 10:58 PM, Jim Kellerman (POWERSET) <
Jim.Kellerman@microsoft.com> wrote:

> Responses inline below.
> > -----Original Message-----
> > From: Slava Gorelik [mailto:slava.gorelik@gmail.com]
> > Sent: Thursday, October 02, 2008 12:39 PM
> > To: hbase-user@hadoop.apache.org
> > Subject: Re: Hbase / Hadoop Tuning
> >
> > Thank You Jim for a quick answer.
> > 1) If i understand correct, using 2 clients should allow me improve
> > the performance twice (more or less) ?
>
> I don't know if you will get 2x performance, but it will be greater than
> 1x.
>
> > 2) Currently, our webapp is HBase client using Htable - is that what you
> > meant, when you said "(HBase, not web) clients" ?
>
> If multiple requests come into your webapp, and your webapp is
> multithreaded, you will not see a performance increase.
>
> If your webapp runs a different process for each request, you will see
> a performance increase because the RPC connection will not be shared
> and consequently will not block on the giant lock. That is why I
> recommended splitting up your job using Map/Reduce.
>
> > 3) 64MB for single region server is a minimum size or could be less ?
>
> It could be less, but that is the default block size for the Hadoop DFS.
> If you make it smaller, you might want to change the default block size
> for Hadoop as well.
>
> > 4) When is planed to fix the RPC lock for concurrent operations
> > in single client ?
>
> This change is targeted for somewhere in the next 6 months according
> to the roadmap.
>
>
> > Thank You Again and Best Regards.
> >
> >
> > On Thu, Oct 2, 2008 at 10:30 PM, Jim Kellerman (POWERSET) <
> > Jim.Kellerman@microsoft.com> wrote:
> >
> > > What you are storing is 140,000,000 bytes, so having multiple
> > > region servers will not help you as a single region is only
> > > served by a single region server. By default, regions split
> > > when they reach 256MB. So until the region splits, all traffic
> > > will go to a single region server. You might try reducing the
> > > maximum file size to encourage region splitting by changing the
> > > value of hbase.hregion.max.filesize to 64MB.
> > >
> > > Using a single client will also limit write performance.
> > > Even if the client is multi-threaded, there is a big giant lock
> > > in the RPC mechanism which prevents concurrent requests (This
> > > is something we plan to fix in the future).
> > >
> > > Multiple clients do not block against one another the way multi-
> > > threaded clients do currently. So another way to increase
> > > write performance would be to run multiple (HBase, not web) clients,
> > > by either running multiple processes directly, or by utilizing
> > > a Map/Reduce job to do the writes.
> > >
> > > ---
> > > Jim Kellerman, Powerset (Live Search, Microsoft Corporation)
> > >
> > >
> > > > -----Original Message-----
> > > > From: Slava Gorelik [mailto:slava.gorelik@gmail.com]
> > > > Sent: Thursday, October 02, 2008 12:07 PM
> > > > To: hbase-user@hadoop.apache.org
> > > > Subject: Re: Hbase / Hadoop Tuning
> > > >
> > > > Hi.Thank you for quick response.
> > > > We are using 7 machines (6 RedHat 5 and 1 is SuSe interprise 10).
> > > > Each machine is : 4 CPU with 4gb ram and 200gb HD, connected with 1gb
> > > > network interface.
> > > > All machines in the same rec. On one machine (master) we are running
> > > > Tomcat
> > > > with one webapp
> > > > that is adding 100000 rows. Nothing else is running. When no webapp
> > > > running
> > > > the CPU load is less the 1%.
> > > >
> > > > We are using Hbase 0.18.0 and Hadoop 0.18.0.
> > > > Hbase cluster is one master and 6 region servers.
> > > >
> > > > Row addition is done by BatchUpdate and commint into single column
> > > family.
> > > > The data is simple bytes array (1400 bytes each row).
> > > >
> > > >
> > > > Thank You and Best Regards.
> > > >
> > > >
> > > >
> > > >
> > > > On Thu, Oct 2, 2008 at 9:39 PM, stack <stack@duboce.net> wrote:
> > > >
> > > > > Tell us more Slava.  HBase versions and how many regions you have
> in
> > > > your
> > > > > cluster?
> > > > >
> > > > > If small rows, your best boost will likely come when we support
> > > batching
> > > > of
> > > > > updates: HBASE-748.
> > > > >
> > > > > St.Ack
> > > > >
> > > > >
> > > > >
> > > > > Slava Gorelik wrote:
> > > > >
> > > > >> Hi All.
> > > > >> Our environment - 8 Datanodes (1 is also Namenode),
> > > > >> 7 from them is also region servers and 1 is Master, default
> > > replication
> > > > -
> > > > >> 3.
> > > > >> We have application that heavy writes with relative small rows
-
> > about
> > > > >> 10Kb,
> > > > >> current performance is 100000 rows in 580000 Milisec - 5.8 Milisec
> > /
> > > > row.
> > > > >> Is there any way to improve this performance by some tuning /
> > tweaking
> > > > >> HBase
> > > > >> or Hadoop ?
> > > > >>
> > > > >> Thank You and Best Regards.
> > > > >>
> > > > >>
> > > > >>
> > > > >
> > > > >
> > >
>

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