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Date: Wed, 29 Jun 2011 09:13:35 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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To: Christoph Hellwig <hch@lst.de>
Cc: Kevin Wolf <kwolf@redhat.com>, Avi Kivity <avi@redhat.com>, Qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

On 06/29/2011 08:50 AM, Christoph Hellwig wrote:
> On Wed, Jun 29, 2011 at 07:23:31AM -0500, Anthony Liguori wrote:
>> Which file system on the host?
>
> Any filesystem.  Although extN and btrfs are particularly bad.
>
>> At any rate, I'm a big fan of making wce tunable in the guest and then I
>> think setting wce=1 is quite reasonable to do by default.
>
> Note that this means a manual override during each boot.  Windows and
> modern Linux just use what's available.  Only Solaris with ZFS actually
> turns WCE on if it's not set AFAIK.  And to me it's a rather questionable
> behaviour at least for SCSI disks where the admin might have chosen
> those intentionally.  (unlike ATA disks SCSI allows to store the setting
> permanently)

Is WCE ever persisted by a disk?  Would it make sense to have a 
mechanism to persist the WCE setting for a guest?

Regards,

Anthony Liguori

>