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] Save/Restore/Reboot FS Corruption

To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Save/Restore/Reboot FS Corruption
From: Mark Williamson <mark.williamson@xxxxxxxxxxxx>
Date: Sat, 15 Mar 2008 02:30:16 +0000
Cc: david.corral@xxxxxxxxxxxxxxxxx
Delivery-date: Fri, 14 Mar 2008 19:30:47 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <20080314111849.n5lccmy0w0g8s40w@xxxxxxxxxxxxxxxxxxxxxxxxx>
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: <20080314111849.n5lccmy0w0g8s40w@xxxxxxxxxxxxxxxxxxxxxxxxx>
Sender: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
User-agent: KMail/1.9.6 (enterprise 0.20070907.709405)
Hrrrmm.  Sounds nasty :-(

> I've been looking for information about this matter, but didn't found
> too much.
>
> Saving and restoring works pretty good, but the problem comes when I
> reboot after
> restoring. FileSystem becomes corrupt after the restoration, so it
> enters "read only"
> status.
>
> Can't provide more info, since I'm far from the computer, only thing I
> can say, its a Debian Etch debootstraped VM, with a ext3-fs.
> The disk image of the VM is stored on a remote storage device, so the
> directory containing the image is mounted via NFS.
>
> Is anyone else experiencing this issue?

What was the sequence of operations that you went through when this happened?  
Something like:

xm save <domain>
... time passes ...
xm restore <domain>
... reboot domain ...
... corruption!

Is it possible that anything modified the domain's virtual disks during 
the "... time passes ..." section above?  Like maybe somebody mounted a 
filesystem in the virtual disk from dom0 for some reason?  Or if somebody 
accidentally did an xm create in the meantime?

Domains will, unfortunately, typically corrupt their virtual disks if their 
filesystem changes whilst they're suspended.  You might not notice this until 
the filesystem gets mounted at reboot time.  Linux doesn't generally expect 
data to change on a disk it thinks it has mounted - even if it's actually xm 
saved at the time - and it can get confused if changes do occur.

Cheers,
Mark

-- 
Push Me Pull You - Distributed SCM tool (http://www.cl.cam.ac.uk/~maw48/pmpu/)

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

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