WARNING - OLD ARCHIVES

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/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] AFS-based VBD backend

To: Luciano Miguel Ferreira Rocha <strange@xxxxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] AFS-based VBD backend
From: Steve Traugott <stevegt@xxxxxxxxxxxxx>
Date: Thu, 23 Dec 2004 03:18:15 -0800
Delivery-date: Thu, 23 Dec 2004 11:19:19 +0000
Envelope-to: xen+James.Bulpin@xxxxxxxxxxxx
In-reply-to: <20041223103717.GA21603@xxxxxxxxxxxxx>
List-archive: <http://sourceforge.net/mailarchive/forum.php?forum=xen-devel>
List-help: <mailto:xen-devel-request@lists.sourceforge.net?subject=help>
List-id: List for Xen developers <xen-devel.lists.sourceforge.net>
List-post: <mailto:xen-devel@lists.sourceforge.net>
List-subscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=subscribe>
List-unsubscribe: <https://lists.sourceforge.net/lists/listinfo/xen-devel>, <mailto:xen-devel-request@lists.sourceforge.net?subject=unsubscribe>
References: <20041223085558.GA29827@xxxxxxxxxxxxx> <20041223103717.GA21603@xxxxxxxxxxxxx>
Sender: xen-devel-admin@xxxxxxxxxxxxxxxxxxxxx
User-agent: Mutt/1.5.6+20040907i
On Thu, Dec 23, 2004 at 10:37:17AM +0000, Luciano Miguel Ferreira Rocha wrote:
> On Thu, Dec 23, 2004 at 12:55:58AM -0800, Steve Traugott wrote:
> > Q:  Why not just use a loop device on top of AFS, with the 'file:' 
> >     VBD type?
> > A:  Loop devices on top of AFS files hang with large volumes of 
> >     I/O -- looks like a deadlock of some sort (in my tests, a dd of
> >     around 2-300 Mb into an AFS-based loop device appears to
> >     consistently hang the kernel, even with a 500Mb or larger AFS
> >     cache).  In addition, an unmodified loop.c will not fsync() the
> >     underlying file; changes won't get written back to the AFS server
> >     until loop teardown.  I've added an fsync() to the worker thread of
> >     loop.c to take care of this every few seconds; that seems to work
> >     but I can't really stress test it much because of the hang problem.

> > What did I miss?  ;-)
> 
> That it's already possible to use normal files. :)
> 
> So, no need for explicit support in xen. If your dom0 already knows and
> uses afs, just specify the file in the xen configuration:
> 
> disk = [ 'file:/afs/file,sda1,w' ]

Already covered in the above FAQ answer.  ;-)  The 'file:...' VBD type
just uses the loop device driver underneath.  Won't work on top of AFS.

Steve
-- 
Stephen G. Traugott  (KG6HDQ)
UNIX/Linux Infrastructure Architect, TerraLuna LLC
stevegt@xxxxxxxxxxxxx 
http://www.stevegt.com -- http://Infrastructures.Org


-------------------------------------------------------
SF email is sponsored by - The IT Product Guide
Read honest & candid reviews on hundreds of IT Products from real users.
Discover which products truly live up to the hype. Start reading now.
http://productguide.itmanagersjournal.com/
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel