| |
|
 |
|
 |
|
|
|
| |
|
|
xen-users
Re: [Xen-users] Swap space for DomU
> but what if the data disk is accessed via AoE mounts (semi equivalent to
> NFS mounts) and the swap disk is in the host machine itself?
> since in this case, the data disk is considered as an "in host" disk, is
> it possible to avoid the migration of data disk, and make the xm live
> migrate remount the appropriate AoE block in the transferred machine?
If the data disk is available by AoE at both the origin host and the
destination host then it should be possible to knock up a script that will
automatically plumb the AoE disk through to the guest when it arrives at its
destination.
But you still need to make sure the same swap volume is available at the other
end too - for instance by using AoE. Otherwise if the guest tries to page
something *in* from swap after migration it won't be able to find it!
Some folks have also experimented with maintaining a VBD image simultaneously
on two hosts and using DRBD to keep them in sync.
But right now, whatever you do, you need to make explicit arrangements for
*all* VBDs seen by the guest to be available, unchanged after a migration.
You can bend this rule in a number of ways but mostly it's a pretty important
guideline.
Cheers,
mark
>
> Mark Williamson wrote:
> > On Friday 28 December 2007, Jan Albrecht wrote:
> >>> What happens with swap space during a live move if I use a file per
> >>> DomU. Does the move script copy the swap file over as well?
> >>
> >> Live move should copy all data disks, which inculdes swap.
> >
> > Nico Kadel-Garcia <nkadel@xxxxxxxxx> Wrote:
> >> If you do a live migration, it does indeed move the state. I like to use
> >> a separate swap partition oon DomU to ease bare metal restorations and
> >> off-line operations on DomU's files.
> >
> > The xm migrate command on its own doesn't copy virtual disks, so neither
> > swap nor data will automatically get migrated with the machine. I think
> > it's possible to configure disk migration using the external device
> > migration scripts, but AFAIK it's not enabled by default - am I wrong
> > here?
> >
> > However, the domain's configuration data is sent along with its memory
> > state when the migration occurs, so if you configure appropriate
> > network-accessible storage for swap and data VBDs then they can be
> > transparently available at the destination machine without the guest
> > knowing what's just happened to it.
> >
> > Cheers,
> > Mark
--
Dave: Just a question. What use is a unicyle with no seat? And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!
_______________________________________________
Xen-users mailing list
Xen-users@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-users
|
|
|
| |
|
Home