This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] [PATCH] Blktap: Userspace file-based image support.(RFC)

To: Andrew Warfield <andrew.warfield@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Blktap: Userspace file-based image support.(RFC)
From: Harry Butterworth <harry@xxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Wed, 05 Jul 2006 02:40:23 +0100
Cc: Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Julian Chesterfield <julian.chesterfield@xxxxxxxxxxxx>, NAHieu <nahieu@xxxxxxxxx>, Dan Smith <danms@xxxxxxxxxx>
Delivery-date: Tue, 04 Jul 2006 18:40:49 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <eacc82a40607041239m141c32a4t3692161fc72cf35f@xxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <A95E2296287EAD4EB592B5DEEFCE0E9D4BAB1A@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <m3psh3pm7t.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <1151674861.7893.5.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <m3hd22ramh.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxx> <1151696271.7893.21.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <1151928154.7699.3.camel@xxxxxxxxxxxxxxxxxxxxx> <1151938599.4785.14.camel@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> <1151941231.7699.18.camel@xxxxxxxxxxxxxxxxxxxxx> <eacc82a40607041239m141c32a4t3692161fc72cf35f@xxxxxxxxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
On Tue, 2006-07-04 at 12:39 -0700, Andrew Warfield wrote:

> > > In principle, with the right software, and configuring your entire
> > > infrastructure from scratch, this sort of device-based mechanism may
> > > work very well.
> >
> > Yes. It does. Here's one we prepared earlier:
> > http://www-03.ibm.com/press/us/en/pressrelease/19705.wss
> I rather doubt that anyone who happens to have purchased SVC as an
> image store is terribly concerned about the ability to lazily copy VM
> images from one local disk to another.

Stephen was talking about a hypothetical cluster aware device
infrastructure and I was pointing out that cluster aware device
infrastructures were already a solved problem and only hypothetical in
the sense that there isn't an open source implementation of one yet.

I was also pointing out that the technique used to create the cluster
aware device infrastructure for SVC which is publicly written up
(amongst other things) here
http://www.research.ibm.com/journal/sj/422/glider.pdf but better
described in purest form here
http://portal.acm.org/citation.cfm?id=279227.279229 can also
conveniently be used to solve almost all the difficult clustering
problems in clustered Xen deployments of which there will be
many--including the problem of making lazy migrations between local
disks on different physical machines sufficiently robust to allow an
enterprise class customer to consider using the feature should we choose
to implement it.


Xen-devel mailing list