[OpenAFS] dbservers version

[Benjamin Kaduk]

On Mon, Dec 12, 2016 at 06:22:51PM +0100, Jean-Marc Choulet wrote:
> Le 12/12/2016 à 17:40, Benjamin Kaduk a écrit :
> > On Mon, Dec 12, 2016 at 04:26:52PM +0100, Jean-Marc Choulet wrote:
> >> Hello,
> >>
> >> At work, we have only one dbserver in version 1.6.1 (Debian 6). We want
> >> to add another dbserver but in a different version : v1.6.9 (Debian 8).
> >> Is it possible without upgrade the first dbserver ?
> > Yes, the database format is unchanged within the major release, so
> > they remain compatible at runtime.  (I am not sure I would say it is "safe"
> > to run them, though, as the Debian 6 version is rather old and has several
> > unpatched bugs that can cause problems in various situations...)
> >
> > -Ben
> Thanks for your advice.
> 
> It's possible for us to upgrade the first dbserver to 1.6.9. If we 
> install a new server with a dbserver version 1.6.9 (same ip of course), 
> is it possible to copy all database files from the old ?

Same IP meaning that the new one will be a drop-in replacement for the old,
and they do not have to speak the ubik protocol to each other?  That should
work fine, just be sure to copy the database files when the relevant server process
is stopped.  This is another consequence of the database format having not
been changed.  (It should even be fine when going to a different endianness,
IIRC, but presumably you're not doing that.)

Jeffrey's comments are mostly only applicable when you have two or more
dbservers running at the same time that are trying to synchronize with
each other (i.e., they are listed in each others' server CellServDB file).
If it is just "bring down one new server, then bring up a new one in its
place", many issues go away.

-Ben