[ovirt-users] 3.6 : Moving the hosted-engine to another storage

[Simone Tiraboschi]

On Wed, Jul 27, 2016 at 5:38 PM, Nir Soffer <nsoffer at redhat.com> wrote:
> On Wed, Jul 27, 2016 at 3:38 PM, Alexis HAUSER
> <alexis.hauser at telecom-bretagne.eu> wrote:
>> Hi,
>>
>> I'm currently using an NFS storage for my hosted-engine. However, this NFS server will be removed soon. I'd like to move the hosted-engine to an iSCSI storage. How can I proceed ? The options for moving/copying VM disk don't seem to be available for the hosted engine in the web interface.
>
> Yes, hosted engine has some limitations at this point, mainly all the
> interesting
> features like live storage migration, live snapshots, hot plug/unplug disk are
> not available.
>
> Simone, do we have a simple procedure to move the engine to another storage?

Theoretically you could run engine-backup on the current engine VM,
redeploy from scratch on the new storage domain and before running
engine setup, inject there the backup.
Something like:
http://www.ovirt.org/develop/developer-guide/engine/migrate-to-hosted-engine/

Unfortunately we know that migrating from HE to HE is not as simple as
from physical to HE:
https://bugzilla.redhat.com/show_bug.cgi?id=1240466#c21
In general the issue is that the DB backup form the old hosted-engine
VM contains a lot of references to the previous hosted-engine env and
you cannot simply remove/edit them from the engine since they are lock
so you have to manually remove them from the DB which is quite
risky/error prone.

Improving engine-backup to automatically filter hosted-engine
references is an RFE for 4.1.

In the mean time I'd suggest, if feasible, to redeploy a new
hosted-engine env and reattach there your storage domains and your
hosts.
This will imply a downtime.

> Nir