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XFS vs Ext3, and schedulers, for WAL
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* XFS vs Ext3, and schedulers, for WAL
@ 2010-10-06 23:11 Josh Berkus <josh@agliodbs.com>
  2010-10-11 17:50 ` Re: XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
  0 siblings, 1 reply; 4+ messages in thread

From: Josh Berkus @ 2010-10-06 23:11 UTC (permalink / raw)
  To: pgsql-performance

All,

There's a number of blog tests floating around comparing XFS and Ext3,
and the various Linux schedulers, for PGDATA or for an all-in-one mount.

However, the WAL has a rather particular write pattern, and it's
reasonable to assume that it shouldn't be optimized the same way as
PGDATA.  Has anyone done any head-to-heads for WAL drive configuration
changes?

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com



^ permalink  raw  reply  [nested|flat] 4+ messages in thread

* Re: XFS vs Ext3, and schedulers, for WAL
  2010-10-06 23:11 XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
@ 2010-10-11 17:50 ` Josh Berkus <josh@agliodbs.com>
  2010-10-11 18:06   ` Re: XFS vs Ext3, and schedulers, for WAL Joshua D. Drake <jd@commandprompt.com>
  0 siblings, 1 reply; 4+ messages in thread

From: Josh Berkus @ 2010-10-11 17:50 UTC (permalink / raw)
  To: pgsql-performance


> There's a number of blog tests floating around comparing XFS and Ext3,
> and the various Linux schedulers, for PGDATA or for an all-in-one mount.
> 
> However, the WAL has a rather particular write pattern, and it's
> reasonable to assume that it shouldn't be optimized the same way as
> PGDATA.  Has anyone done any head-to-heads for WAL drive configuration
> changes?

That would be a "no", then.  Looks like I have my work cut out for me ...

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com



^ permalink  raw  reply  [nested|flat] 4+ messages in thread

* Re: XFS vs Ext3, and schedulers, for WAL
  2010-10-06 23:11 XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
  2010-10-11 17:50 ` Re: XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
@ 2010-10-11 18:06   ` Joshua D. Drake <jd@commandprompt.com>
  2010-10-11 18:59     ` Re: XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
  0 siblings, 1 reply; 4+ messages in thread

From: Joshua D. Drake @ 2010-10-11 18:06 UTC (permalink / raw)
  To: Josh Berkus <josh@agliodbs.com>; +Cc: pgsql-performance

On Mon, 2010-10-11 at 10:50 -0700, Josh Berkus wrote:
> > There's a number of blog tests floating around comparing XFS and Ext3,
> > and the various Linux schedulers, for PGDATA or for an all-in-one mount.
> > 
> > However, the WAL has a rather particular write pattern, and it's
> > reasonable to assume that it shouldn't be optimized the same way as
> > PGDATA.  Has anyone done any head-to-heads for WAL drive configuration
> > changes?
> 
> That would be a "no", then.  Looks like I have my work cut out for me ...

The only thing I have done is:

http://www.commandprompt.com/blogs/joshua_drake/2008/04/is_that_performance_i_smell_ext2_vs_ext3_on_...

It doesn't cover XFS but it provides a decent and simple comparison on
ext2/ext3 etc...

Remember xlog is sequential so pushing it off is useful.

JD

> 
> -- 
>                                   -- Josh Berkus
>                                      PostgreSQL Experts Inc.
>                                      http://www.pgexperts.com
> 

-- 
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^ permalink  raw  reply  [nested|flat] 4+ messages in thread

* Re: XFS vs Ext3, and schedulers, for WAL
  2010-10-06 23:11 XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
  2010-10-11 17:50 ` Re: XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
  2010-10-11 18:06   ` Re: XFS vs Ext3, and schedulers, for WAL Joshua D. Drake <jd@commandprompt.com>
@ 2010-10-11 18:59     ` Josh Berkus <josh@agliodbs.com>
  0 siblings, 0 replies; 4+ messages in thread

From: Josh Berkus @ 2010-10-11 18:59 UTC (permalink / raw)
  To: Joshua D. Drake <jd@commandprompt.com>; +Cc: pgsql-performance


> http://www.commandprompt.com/blogs/joshua_drake/2008/04/is_that_performance_i_smell_ext2_vs_ext3_on_...
> 
> It doesn't cover XFS but it provides a decent and simple comparison on
> ext2/ext3 etc...

Yeah, it doesn't test actual log writing, though.  Nor specific settings
even for those two filesystems.  So it's still a mystery ...

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com



^ permalink  raw  reply  [nested|flat] 4+ messages in thread


end of thread, other threads:[~2010-10-11 18:59 UTC | newest]

Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2010-10-06 23:11 XFS vs Ext3, and schedulers, for WAL Josh Berkus <josh@agliodbs.com>
2010-10-11 17:50 ` Josh Berkus <josh@agliodbs.com>
2010-10-11 18:06   ` Joshua D. Drake <jd@commandprompt.com>
2010-10-11 18:59     ` Josh Berkus <josh@agliodbs.com>

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