From: Neil Brown <neilb@suse.de>
To: David Chinner <dgc@sgi.com>
Cc: Neil Brown <neilb@suse.de>, Timothy Shimmin <tes@sgi.com>,
xfs@oss.sgi.com
Subject: Re: XFS and write barriers.
Date: Mon, 26 Mar 2007 10:01:01 +1000 [thread overview]
Message-ID: <17927.3389.655835.610940@notabene.brown> (raw)
In-Reply-To: message from David Chinner on Sunday March 25
On Sunday March 25, dgc@sgi.com wrote:
> On Fri, Mar 23, 2007 at 07:00:46PM +1100, Neil Brown wrote:
> >
> > Why no barriers on an external log device??? Not important, just
> > curious.
>
> because we need to synchronize across 2 devices, not one, so issuing
> barriers on an external log device does nothing to order the metadata
> written to the other device...
Right, of course. Just like over a raid0.
So you must have code to wait for all writes to the main device before
writing the commit block on the journal. How hard is it to fall-back
to that if the barrier fails?
NeilBrown
next prev parent reply other threads:[~2007-03-26 0:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-23 1:26 XFS and write barriers Neil Brown
2007-03-23 5:30 ` David Chinner
2007-03-23 7:49 ` Neil Brown
2007-03-25 4:17 ` David Chinner
2007-03-25 23:21 ` Neil Brown
2007-03-26 3:14 ` David Chinner
2007-03-26 4:27 ` Neil Brown
2007-03-26 9:04 ` David Chinner
2007-03-29 14:56 ` Martin Steigerwald
2007-03-29 15:18 ` David Chinner
2007-03-29 16:49 ` Martin Steigerwald
2007-03-23 9:50 ` Christoph Hellwig
2007-03-25 3:51 ` David Chinner
2007-03-25 23:58 ` Neil Brown
2007-03-26 1:11 ` Neil Brown
2007-03-23 6:20 ` Timothy Shimmin
2007-03-23 8:00 ` Neil Brown
2007-03-25 3:19 ` David Chinner
2007-03-26 0:01 ` Neil Brown [this message]
2007-03-26 3:58 ` David Chinner
2007-03-27 3:58 ` Timothy Shimmin
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