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From: Brian Candler <B.Candler@pobox.com>
To: Dave Chinner <david@fromorbit.com>
Cc: David Fuller <dfuller@epoch.com>, xfs@oss.sgi.com
Subject: Re: Fragmentation Issue We Are Having
Date: Tue, 17 Apr 2012 09:58:28 +0100	[thread overview]
Message-ID: <20120417085828.GA13168@nsrc.org> (raw)
In-Reply-To: <20120417002610.GC6734@dastard>

On Tue, Apr 17, 2012 at 10:26:10AM +1000, Dave Chinner wrote:
> > > You can't just blindly assert that something is needed purely on
> > > the size of the filesystem.
> > 
> > Thanks, but then perhaps the XFS FAQ needs updating. It warns that you might
> > have compatibility problems with old clients (NFS) and inode64, but it
> > doesn't say "for some workloads inode32 may perform better than inode64 on
> > large filesystems".
> 
> The FAQ doesn't say anything about whether inode32 performs better
> than inode64 or vice versa.

With respect it does, although in only three words:
"Also, performance sucks".

Maybe it would be useful to expand this. How about:

"Also, performance sucks for many common workloads and benchmarks, such as
sequentially extracting or reading a large hierarchy of files.  This is
because in filesystems >1TB without inode64, files created within the same
parent directory are not created in the same allocation group with adjacent
extents."

If as you say inode32 was just a hack for broken NFS clients, then it seems
to me that the *intended* default performance characteristics are those of
inode64?  That is, the designers considered this to be the most appropriate
performance compromise for typical users?

Regards,

Brian.

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  reply	other threads:[~2012-04-17  8:58 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-12  1:04 Fragmentation Issue We Are Having David Fuller
2012-04-12  2:16 ` Dave Chinner
2012-04-12  2:55   ` David Fuller
2012-04-12  4:24     ` Eric Sandeen
2012-04-12  7:57 ` Brian Candler
2012-04-13  0:09   ` David Fuller
2012-04-13  7:19     ` Brian Candler
2012-04-13  7:56       ` Dave Chinner
2012-04-13  8:17         ` Brian Candler
2012-04-17  0:26           ` Dave Chinner
2012-04-17  8:58             ` Brian Candler [this message]
2012-04-18  1:36               ` Dave Chinner
2012-04-18  9:00                 ` Brian Candler
2012-04-19 23:12                   ` Dave Chinner
  -- strict thread matches above, loose matches on Subject: below --
2012-04-19 19:54 Richard Scobie

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