[OpenAFS] DB servers seperate from fileservers

Ken Hornstein kenh@cmf.nrl.navy.mil
Tue, 08 Aug 2006 13:25:36 -0400

>I was specifically talking about DB servers.  Having one of them go 
>down, provided there are no volumes on that server, should not cause a 
>problem, right?

In theory, no.  In practice ... it's annoying.

The problem is that AFS clients pick a DB server to talk to at random,
and for most cases stick with that server.  For a long-running bit of
software like the cache manager, a single server going down isn't a huge
problem; the client notices that server X is down, and then won't use
that server again.  But for userland programs, they have no idea what
the current state is for ubik servers, so they pick one at random ...
and sometimes they pick the down one, and you get delays when using
"vos" or "pts".  Those commands will eventually work ... they just
sometimes take a while to find the right DB servers.