[DRBD-user] Uncatchable DRBD out-of-sync issue

[Dan Barker]

> -----Original Message-----
> From: drbd-user-bounces at lists.linbit.com [mailto:drbd-user-
> bounces at lists.linbit.com] On Behalf Of Stanislav German-Evtushenko
> Sent: Monday, March 25, 2013 10:13 AM
> To: Radu Radutiu
> Subject: Re: [DRBD-user] Uncatchable DRBD out-of-sync issue
> 
> Thank you for suggestion.
> 
> I could investigate if this is a swap region but it wouldn't help
> because:
> 1) I can check it for Linux VMs but I can't do the same for Windows
> ones (because swap file is in file system).
> 2) I can't do online migration even if only swap region is out of sync
> because it will make a VM unstable.
> 
> On Mon, Mar 25, 2013 at 5:07 PM, Radu Radutiu <rradutiu at gmail.com> wrote:
> > I was asking if the out of sync blocks belong to a swap partition of
> one of
> > the virtual machines. I see exactly the same problem with a setup more
> or
> > less similar to your setup (my setup is an active-passive one, lvm on
> top
> > dbrb, with kvm virtual machines using these logical volumes as
> storage).
> > I seem to recall some older messages on drbd list stating that it might
> be
> > OK to have oos blocks for the swap device.
> >
> > Best Regards,
> >
> > Radu
> >
> >
> 

You don't need Dual-Primary to live migrate - you need shared storage. Two completely different concepts. Now, the shared storage can be based on a DRBD Primary, and you can have it fail over to a DRBD Secondary, but dual primary is not going to do what you want and shared storage will. The storage you share may be virtualized, if you like.

Dan