From: Kevin Wolf <kwolf@redhat.com>
To: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Andrew Theurer <habanero@linux.vnet.ibm.com>,
qemu-devel@nongnu.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [Qemu-devel] [PATCH] block: add cache=directsync parameter to -drive
Date: Wed, 03 Aug 2011 17:22:28 +0200 [thread overview]
Message-ID: <4E3967B4.8080608@redhat.com> (raw)
In-Reply-To: <1312191547-12777-1-git-send-email-stefanha@linux.vnet.ibm.com>
Am 01.08.2011 11:39, schrieb Stefan Hajnoczi:
> This patch adds -drive cache=directsync for O_DIRECT | O_SYNC host file
> I/O with no disk write cache presented to the guest.
>
> This mode is useful when guests may not be sending flushes when
> appropriate and therefore leave data at risk in case of power failure.
> When cache=directsync is used, write operations are only completed to
> the guest when data is safely on disk.
>
> This new mode is like cache=writethrough but it bypasses the host page
> cache.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
qemu-img has another parser for cache options that must be changed. This
should probably be refactored to a single implementation in block.c.
Kevin
prev parent reply other threads:[~2011-08-03 15:20 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-01 9:39 [Qemu-devel] [PATCH] block: add cache=directsync parameter to -drive Stefan Hajnoczi
2011-08-03 15:22 ` Kevin Wolf [this message]
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