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From: Al Boldi <a1426z@gawab.com>
To: NeilBrown <neilb@cse.unsw.edu.au>, Andrew Morton <akpm@osdl.org>
Cc: linux-raid@vger.kernel.org
Subject: Re: [PATCH md 006 of 6] Add write-behind support for md/raid1
Date: Fri, 12 Aug 2005 09:22:52 +0300	[thread overview]
Message-ID: <200508120922.52689.a1426z@gawab.com> (raw)
In-Reply-To: <E1E37OV-0002jU-9q@notabene.cse.unsw.edu.au>

NeilBrown wrote:
> If a device is flagged 'WriteMostly' and the array has a bitmap,
> and the bitmap superblock indicates that write_behind is allowed,
> then write_behind is enabled for WriteMostly devices.

Nice, but why is it dependent on WriteMostly?

> This requires memory allocation to make a local copy of the data
> being written.  If there is insufficient memory, then we fall-back
> on normal write semantics.

Good!

Also, it would be nice to have something like:
echo 1 > /proc/md../../WriteBehindEnabled
echo 10 > /proc/md../../WriteBehindMaxDelayBeforeSync

Thanks!

--
Al


  reply	other threads:[~2005-08-12  6:22 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-11  7:22 [PATCH md 000 of 6] Introduction NeilBrown
2005-08-11  7:22 ` [PATCH md 001 of 6] Make sure mddev->bitmap_offset gets cleared between array instantiations NeilBrown
2005-08-11  7:22 ` [PATCH md 003 of 6] Improve handling of bitmap initialisation NeilBrown
2005-08-11  7:22 ` [PATCH md 002 of 6] Don't allow new md/bitmap file to be set if one already exists NeilBrown
2005-08-11  7:22 ` [PATCH md 005 of 6] Support write-mostly device in raid1 NeilBrown
2005-08-11  8:51   ` RAID5 spare change djani22
2005-08-11 10:08     ` Neil Brown
2005-08-11  7:22 ` [PATCH md 006 of 6] Add write-behind support for md/raid1 NeilBrown
2005-08-12  6:22   ` Al Boldi [this message]
2005-08-12 12:15     ` Paul Clements
2005-08-13  5:00       ` Al Boldi
2005-08-14 22:24         ` Neil Brown
2005-08-15  4:45           ` Al Boldi
2005-08-14 22:16     ` Neil Brown
2005-08-11  7:22 ` [PATCH md 004 of 6] All hot-add and hot-remove of md intent logging bitmaps NeilBrown

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