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From:dbrb2002-sql Date:March 7 2009 1:21am
Subject:Re: MySQL Log and Data directories
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Thanks Baron...

Also, curious question.. as you might have used what is called GOOD hw configurarion with
RAID 5/10 .. so whats the typical IO (rnd rw) that you archive/expect on high trafficked
sites ?

--- On Wed, 3/4/09, Baron Schwartz <baron@stripped> wrote:

From: Baron Schwartz <baron@stripped>
Subject: Re: MySQL Log and Data directories
To: dbrb2002-sql@stripped
Cc: mysql@stripped
Date: Wednesday, March 4, 2009, 11:40 AM

On Wed, Mar 4, 2009 at 1:22 PM,  <dbrb2002-sql@stripped> wrote:
> On a high read/write load.. is it good to split log (binlogs, innodb txn logs) and
> data (all tables, innodb tablespace) in different partitions ?
>
> Anybody had any experience ?
>
> For example; out of 25 disks array with 142GB 10000rpm... I would like to keep few
> disks to logs and rest to data .. is it advised or better to keep everything in spool so
> that all spindles can be efficiently managed...
>
> Thanks in advance

There are exceptions to everything I'm about to write, but:

Under high read loads, there is no benefit.  Under high write loads,
there might be.  With this many disks, yes.  With fewer disks, the
relatively trivial sequential log writes will not actually degrade
performance much, and the non-trivial performance impact of stealing
disks away and dedicating them to the logging workload will make a lot
of difference.

The real answer is always -- run a benchmark and see.  Does the
improvement offset things like any kind of penalty the OS imposes on
you (e.g. LVM can't take a snapshot across multiple volumes)?


-- 
Baron Schwartz, Director of Consulting, Percona Inc.
Our Blog: http://www.mysqlperformanceblog.com/
Our Services: http://www.percona.com/services.html

Thread
MySQL Log and Data directoriesdbrb2002-sql4 Mar
  • Re: MySQL Log and Data directoriesMichael Dykman4 Mar
    • Re: MySQL Log and Data directoriesChaim Rieger4 Mar
  • Re: MySQL Log and Data directoriesBaron Schwartz4 Mar
Re: MySQL Log and Data directoriesdbrb2002-sql4 Mar
Re: MySQL Log and Data directoriesdbrb2002-sql7 Mar
  • Re: MySQL Log and Data directoriesBaron Schwartz7 Mar