From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:53791) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QbvAT-0001Nn-Vn for Qemu-devel@nongnu.org; Wed, 29 Jun 2011 09:51:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QbvAS-0004qu-Im for Qemu-devel@nongnu.org; Wed, 29 Jun 2011 09:51:01 -0400 Received: from verein.lst.de ([213.95.11.211]:42760 helo=newverein.lst.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QbvAR-0004q4-RO for Qemu-devel@nongnu.org; Wed, 29 Jun 2011 09:51:00 -0400 Date: Wed, 29 Jun 2011 15:50:59 +0200 From: Christoph Hellwig Message-ID: <20110629135059.GB15863@lst.de> References: <4E0B1399.4050807@redhat.com> <4E0B152B.1000201@codemonkey.ws> <4E0B1787.30709@redhat.com> <4E0B1943.4090400@codemonkey.ws> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E0B1943.4090400@codemonkey.ws> Subject: Re: [Qemu-devel] Default cache mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Kevin Wolf , Avi Kivity , Christoph Hellwig , Qemu-devel@nongnu.org, Stefan Hajnoczi 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)