----- Original Message -----

From: "Robert Story" <rstory@tislabs.com> To: Users@ovirt.org Sent: Wednesday, February 18, 2015 5:12:40 PM Subject: [ovirt-users] how to prepare for an engine re-install

I'm running ovirt (engine 3.4.0-1.el6) on a dedicated engine machine with a degraded raid array. This has caused the root filesystem to go read-only, and the engine crashed. I can restart the engine, but after doing so, the web page just loads a blank page. All nodes and VMs seem to be fine, I just can't manage them via oVirt.

Because I'm offsite, my recovery option is likely limited to a reinstall of the OS and ovirt. I'm hoping for some pointers on what I can do in advance to minimize the pain of this transition.

- Am I going to be able to recover without having to shut down VMs, exporting and importing?

Perhaps, depends on your plan

- what directories should I back up?

If at all possible, you should try engine-backup. I guess it will fail if the fs is read-only, because postgres will not start and engine-backup uses it. You might get by with copying the stuff engine-backup does (search for BACKUP_PATHS in its start), and also a cold copy of the database - all of /var/lib/pgsql/data . Try copying the db to another machine and 'service postgresql start'. If it works, and you can connect to the db, full recovery will probably work.

- when I reinstall, should I upgrade and install 3.5.1, or first install 3.4, get it working, and then think about upgrading?

I'd separate them. Reinstall with exact same version if possible - not sure you can find 3.4.0 on the yum repo, perhaps you can find somewhere in your cache the version you use, or something like that - then upgrade when all is quiet.

- Is it possible/recommended/crazy to migrate to a hosted engine instead of a dedicated machine?

In principle should be possible.

So I want to prepare for the worst before I try a reboot.

If it's currently read-only, why not simply copy all of it somewhere? Then if a reboot kills it, you still have the copy to try and recover from.

If I'm lucky, the reboot will at least come up with a writable filesystem, and I won't need to re-install. If it doesn't come up, I want to be as ready as possible for the reinstall.

Any hints and/or tips appreciated..

If at all possible, practice on a test system before trying live :-) See [1] for an overview of a migration to hosted-engine. Most of it is relevant to any migration, if engine-backup works for you. Otherwise it's even simpler - just copy files and hope that postgresql will manage to work with the db. [1] http://www.ovirt.org/Migrate_to_Hosted_Engine Good luck and best regards, -- Didi