[OpenAFS] Moving volumes

Steve Devine sdevine@msu.edu
Fri, 13 Oct 2006 19:48:50 -0400

Juha Jäykkä wrote:
>> up things my moving volumes to the new server only to realize that I
>> did something wrong in the process. I though that "copying" ( if such a 
>> thing exists) would be safer. But from the response of  Russ only one 
>> copy should exist on a cell so I am not really sure what to do.
> I'm not sure, if this will work, but it SHOULD. Someone with more
> experience and knowledge may want to confirm whether I'm right or not.
> Anyway, if you're really paranoid about it, you might just do this for
> all your volumes:
> 1) vos addsite -server old -partition /wherever_it_is_NOW -id volume_name
> 2) vos addsite -server new -partition /wherever_it_fits -id volume_name
> 3) vos release volume_name
> 4) vos move -id volume_name -fromserver old -frompartition /wherever_it_is_NOW -toserver new -topartition /wherever_it_fits
> This way you'll have two copies at all times, but still end up having
> moved the read-write volume to the new server. The addsite commands just
> set up two read-only replicas.
> Next, you'll replicate the DB server, too. Easiest way to do this is to
> create an upserver process on the old machine and an upclient process on
> the new host. (Read the AFSLore or man bos_create for details.) Adding DB
> servers to an AFS cell is rather tricky for the *clients*, so you'll need
> to be sure you do it right; otherwise your client will lose access to
> their files (nothing serious, just inconvenient: it can be fixed easily).
> At this point you can test how things work by unplugging the network from
> the old server - if things go wrong, you just plug it back.
> If everything works, just use "vos remsite" to remove the RO replicas
> from the old server and "bos delete" to remove the upclient and upserver
> processes. After that, just scrap the old server.
> -Juha
My 2 cents:
  Trust afs to do the right thing. If your cell is healthy you will not
lose a volume during a vos move. Best advice is create a volume on old
server load it with some data and "vos move" it to your new server if
you want to test it.  Do Not use a unix command like mv or cp or tar.
Just let afs do it. I move volumes all the time and my users don't even
know it.

Steve Devine
Storage Systems
Academic Computing & Network Services
Michigan State University

506 Computer Center
East Lansing, MI 48824-1042

Baseball is ninety percent mental; the other half is physical.
- Yogi Berra