Some thoughts on enhancing High Availability in oVirt

[Caitlin Bestler]

Yaniv Kaul wrote:

> I think migrating a paused VM (due to EIO) is something KVM is afraid to do - there might be in-flight
> (in the host already) data en-route to the storage.
> I'm not entirely sure how you migrate the storage, when it's failed.

A Storage Service that is already defined to be highly available should be usable by an HA VM without any problem.
When you migrate a VM the current operations all fail, but the storage stack merely retries them.

There are even solutions for dealing with storage targets that were on the intra-host IP subnet. See my presentation
On NAS proxies at last year's Xen Summit:
http://xen.org/files/xensummit_santaclara11/aug2/11_Bestler_Tailoring_NAS_Proxies_for_Virtual_Machines.pdf