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-users

Re: [Xen-users] Share of disks in read only between dom0 and domU.

To: James Harper <james.harper@xxxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] Share of disks in read only between dom0 and domU.
From: Michel Gaudet <Michel.Gaudet@xxxxxxxx>
Date: Thu, 27 Sep 2007 12:02:41 +0200
Cc: xen-users@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 01 Oct 2007 09:55:25 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <AEC6C66638C05B468B556EA548C1A77D012498E6@trantor>
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/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-users>, <mailto:xen-users-request@lists.xensource.com?subject=unsubscribe>
References: <46FB61FD.5010709@xxxxxxxx> <AEC6C66638C05B468B556EA548C1A77D012498E6@trantor>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: Thunderbird 1.5.0.9 (X11/20061206)
Hello !

James Harper a écrit :
Hello !

Because of a special config of my grub boot system, i try to export in
a
domU, in read
only mode, one of my disk partition mounted in the dom0 (in RW)  and i
don't succeed
because xen refuse to export this disk partition in a domU.


I think you can append a '!' do the permissions, eg 'r!' or 'w!' (or
maybe it was a '+'?) if you want to force xen to do your bidding, even
if xen thinks it's not a good idea. I've done this with OCFS2 before.


I tried this before but neither ! nor + works on my xen (3.0.3 in SuSE 10.2).
I get :
Error: Invalid mode


But for a non-cluster aware filesystem, you're asking for trouble. DomU
will cache filesystem data which Dom0 may write to, leaving DomU with
out of data information (nothing to tell it to re-read). If everyone
mounts the filesystem ro then you should be fine

I think you can configure Dom0 to mount the filesystem with no write
caching (eg synchronous mode), but I don't think you can tell DomU to
mount it with no read caching, and even if you could, you would surely
run into race conditions where Dom0 is changing data even as DomU is
reading it.

James


It is only for grub to see its differents stages (1.5 and 2) which are located on /dev/sda6 and it is no need at all to access this disk after booting the XP.
I don't know really if my idea is good but all the others tries did not work.

Thanks.

--
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

   ^  ^ ----           Michel GAUDET          +--- |  | +--- +--- +---
  /| /||    |            CRI/SIR              |__  |__| |__  |__  |__
 / |/ ||  __      Ecole des Hautes Etudes     |    |  | |       |    |
/     ||____|       en Sciences Sociales      +--- |  | +--- ---+ ---+
              54 Boulevard RASPAIL 75006 PARIS
    Tel:(33) 01 49 54 25 91           Email: Michel.Gaudet@xxxxxxxx
    FAX:(33) 01 49 54 26 85

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

<Prev in Thread] Current Thread [Next in Thread>