[libvirt-users] RAID1 over IP?

[David Ehle]

On Tue, 19 Jul 2011, Emmanuel Noobadmin wrote:

> On 7/19/11, David Ehle <ehle at agni.phys.iit.edu> wrote:
>> KVM/libvirt makes moving running VM's from one host to another a no
>> brainer, but I'm trying to figure out the right way to be able to take a
>> the storage backend for maintenance without disrupting the VMs.
>>
>> Right now I'm thinking something like KVM + libvirt + heartbeat/corosync +
>> pacemaker + DBRM on Ubuntu 10.04 with 3 or 4 nodes - 2 hosts, 2 storage,
>> or 1 host, 1 host + storage, 1 storage.
>
> Personally, I had been planning to do it with mdadm multi-path & RAID
> 1 over iSCSI. Seems to be a more straightforward solution than using a
> full HA setup if the purpose is to ensure storage remains available
> when a node is down (for maintenance or otherwise).
>
>

Would you be willing /able to elaborate more on this idea?  I've been 
looking into it a bit more and while your right that it sounds simpler on 
paper, it looks like doing DRBD is packaged for Ubuntu, and there is 
pretty good Cook Book documentation for how to do HA NFS on top of DRBD.

I'm a real novice on the multipath topic so I'm having trouble comparing 
apples to apples to see what the pros and cons of the two scenarios would 
be.

Thanks!

David.