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From: Robert Watson <rwatson@FreeBSD.org>
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To: Pawel Jakub Dawidek <pjd@FreeBSD.org>
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Cc: freebsd-fs@freebsd.org, freebsd-current@freebsd.org,
	Sean Bryant <bryants@gmail.com>, freebsd-geom@freebsd.org
Subject: Re: GJournal (hopefully) final patches.
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On Fri, 11 Aug 2006, Pawel Jakub Dawidek wrote:

> 2. Confirm that partition with your file system is _not_ 4 sectors
>   aligned. If it is not 4 sectors aligned, it is safe for gjournal to
>   use its last sector for metadata. You can verify this by running:
>
> 	test `diskinfo /dev/<data_partition> | awk '{print $4}' | xargs -J X echo X % 4 | bc` -eq 0 && echo ok || echo not ok
>
> Then you need to run those commands:
>
> 	# gjournal label /dev/<data_partition> /dev/<journal_partition>
> 	# tunefs -n disable -J enable /dev/<data_partition>.journal

Sounds like a "gjournal testalignment /dev/partition" would be a very useful 
thing.  Or even just doing it as part of gjournal label?

Robert N M Watson
Computer Laboratory
University of Cambridge