[OpenAFS] DB servers: simultaneous use of 2 OpenAFS versions

[John Hascall]

> We have 3 DB servers to upgrade, hardware + OS + OpenAFS (1.2.13 to 1.4.1).
> These upgrades imply moving the data volumes out of the old server, 
> doing hardware and software install, and moving the data back into the 
> new server.
> I estimate that upgrading one server could take about 3 days (most of it 
> used for transfers), and I can upgrade only one at a time (spare room 
> for moved data).
> 
> This means that, during about 10 days, DB servers with 2 different 
> versions of OpenAFS will have to cohabit (1 x 1.4.1 and 2 x 1.2.13, then 
> 2 x 1.4.1 and 1 x 1.2.13, before the final 3 x 1.4.1).
> 
> Once upon a time, AFS documentation said that all DB servers must run 
> the same AFS version, and so that they should be upgraded in the 
> shortest lapse of time.
> Is this still true? Is the above 10 days cohabitation possible, or what 
> are the problems likely to arise?

I suspect it will work.  None the less it sounds like you
have put fileservers on your DB servers.  This is really
not ideal.  Since you seem to have new hardware in hand,
you might consider this as an opportunity to split your
DB and fileserver functions across machines.  A DB(only) server
typically needs far less resources than a fileserver, so
running them on less-capable hardware is fine.

John