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Re: External Journal and ACL Support

To: Mike Young <myoung@xxxxxxxxxxxxxxxxxxx>
Subject: Re: External Journal and ACL Support
From: Nathan Scott <nathans@xxxxxxx>
Date: Wed, 24 Mar 2004 09:52:06 +1100
Cc: linux-xfs@xxxxxxxxxxx
In-reply-to: <200403230115.RAA27552@amber.he.net>
References: <20040322233621.GG699@frodo> <200403230115.RAA27552@amber.he.net>
Sender: linux-xfs-bounce@xxxxxxxxxxx
User-agent: Mutt/1.5.3i
On Mon, Mar 22, 2004 at 05:16:51PM -0800, Mike Young wrote:
> Hi Nathan,
> 
> ...
> At this point, I should point out that I've just realized that my default
> inode size is not 1k, but rather 256.  I'm also specifying sunit and swidth,

:)  I thought that might be the case, the difference in performance
was inexplicable to me otherwise.

> you may still be interested in the performance impact described below.
> Again, when I say "with acls", the inode size is 256.

Yep.

> Also, as far as performance goes, when acls are turned off, and the journal
> is placed on an external device, the nbench throughput is 60MB/sec at 6
> clients.  It tapers off to 53MB/sec at 32 clients.  However, when I turn
> acls on, my peak is 40MB/sec at 4 clients and drops to 26MB/sec at 30
> clients.  If I rerun the last test, but with the internal journal, my peak
> goes back up to 52MB/sec and the low is 37MB/sec.

OK, I can understand that with non-inline attrs (there's more I/O
involved, and the additional read can only happen after the inode
has first been read)

> I'll let you know how things go.

Great, thanks Mike.

cheers.

-- 
Nathan


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