xen-users

[Top] [All Lists]

Re: [Xen-users] write through or write back?

from [Pasi Kärkkäinen]

[Permanent Link][Original]

To:	Lei Lu <lulei.wm@xxxxxxxxx>
Subject:	Re: [Xen-users] write through or write back?
From:	Pasi Kärkkäinen <pasik@xxxxxx>
Date:	Tue, 23 Nov 2010 21:23:13 +0200
Cc:	xen-users <xen-users@xxxxxxxxxxxxxxxxxxx>
Delivery-date:	Tue, 23 Nov 2010 11:30:49 -0800
Envelope-to:	www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to:	<AANLkTimTzYdLa8sTe06z+Lv6qXawmAuNKr6A+3zUHB_f@xxxxxxxxxxxxxx>
List-help:	<mailto:xen-users-request@lists.xensource.com?subject=help>
List-id:	Xen user discussion <xen-users.lists.xensource.com>
List-post:	<mailto:xen-users@lists.xensource.com>
List-subscribe:	<http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe:	<http://lists.xensource.com/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References:	<AANLkTimTzYdLa8sTe06z+Lv6qXawmAuNKr6A+3zUHB_f@xxxxxxxxxxxxxx>
Sender:	xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent:	Mutt/1.5.18 (2008-05-17)

On Mon, Nov 22, 2010 at 12:18:13PM -0500, Lei Lu wrote:
> Hi everyone,
> 
> Can anybody clarify about what disk cache mechanism the current Xen
> hypervisor use? is it write through or write back? Is there a way to
> change between this two modes? As far as I know, the original linux
> kernel implements the disk cache as page cache and the flusher thread
> may periodically flush the dirty pages to the disk. Does Xen still use
> this strategy by default or not?
> 

Hey,

Actually Xen *hypervisor* itself doesn't affect this..
it depends on your dom0 setup.. ie. what disk backend you 
choose for the guest vm virtual disks.

file: backed disks use dom0 linux kernel caching, 
but tap:aio: or phy: backed disks don't..

-- Pasi


_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users

[More with this subject...]

<Prev in Thread]	Current Thread	[Next in Thread>
[Xen-users] write through or write back?, Lei Lu Re: [Xen-users] write through or write back?, Pasi Kärkkäinen <=

Previous by Date:	Re: [Xen-devel] Re: [Xen-users] [HOWTO] Running Xen 4.0 host (dom0) with Redhat Enterprise Linux 6 (RHEL6) xen fails to build, Boris Derzhavets
Next by Date:	Re: [Xen-users] help, George Shuklin
Previous by Thread:	[Xen-users] write through or write back?, Lei Lu
Next by Thread:	[Xen-users] HVM error on booting, David Cemin
Indexes:	[Date] [Thread] [Top] [All Lists]