[OpenAFS] AFS Database Server migration - advice sought

Simon Wilkinson sxw@inf.ed.ac.uk
Mon, 8 Mar 2010 10:16:27 +0000

On 8 Mar 2010, at 07:21, Robert Sturrock wrote:
> .. and what I want to move to instead is:
>    hermes1 (VM) - RHEL5, OpenAFS 1.4.10
>    hermes2 (VM) - RHEL5, OpenAFS 1.4.10
>    hermes3 (VM) - RHEL5, OpenAFS 1.4.10
> ie. replace physical machine "telos" with a VM.

Just a quick sanity check here - I trust all of these VMs aren't  
hosted on the same physical hardware?

> The new VM is configured (it's just a clone of hermes2 with the
> name/IP changed).  I'm wondering if I can simply shutdown telos and
> bring up hermes3 with its IP address?  The hostname will obviously be
> different - I'm not sure if that matters to database servers.  (The
> client CellServDB files use IPs and CNAMEs so that should be ok).

We did this kind of migration very recently. The steps essentially are:

0) Take backups
Take backups of the existing databases, just in case anything goes  
wrong. For extra safety, we also used pt_util to dump the ptserver  

1) Stop old database server.
This will cause a short hang of just under a minute for approximately  
one third of your clients, as they notice that the server is down.

2) Configure new database server.
Configure bos on the new database server, and install a copy of your  
cells KeyFile. For safety, make sure that /usr/afs/db on this machine  
is empty.

3) Bring up new database server on same IP as old server

4) Check everything is OK
Look at the logs in /usr/afs/logs on the new server to make sure there  
are no complaints.  Run udebug on the ptserver and vlserver ports to  
check that the recovery state is '2f'

5) Make sure that there's absolutely no way the old DB server can be  
turned back on.
I'll leave this to your imagination...

Hope that helps,