Troy,
Here at SAS Institute, Inc. in Cary, NC, we have 5 AFS
DataBase servers running, one each per FDDI sub-ring. We run
the DataBase servers on dedicated machines to optimize uptime.
You MUST run file server processes on database servers for all
of IP ports to work correctly. However, if you don't put actual
partitions and files on the DB server, then they will come on-line
faster (no salvages to run, no volumes to attach, etc.) Since the
DB servers usually come back on-line faster than file servers,
especially after an "unscheduled" outage, the file servers don't
have to wait for quorum to selected.
We do run other "database"s on these servers, mainly "name service."
The additional load has not caused any noticeable impact and has the
additional benefit of limiting which machines MUST be on-line first.
A final benefit is isolation of problems. If a Database server
starts "losing it", you can take it off-line without impacting file
service. (Obviously, replicated databases help here! :)
Hope some/all of this helps!
========================================================================
Bob Janka SAS Institute, Inc. Any opinions
Systems Developer SAS Campus Drive expressed are
Development Source Management Cary, NC 27513 mine, of course
[EMAIL PROTECTED] (919) 677-8000 x7788
Date: Wed, 26 Oct 1994 06:55 -0700 (PDT)
From: [EMAIL PROTECTED]
Subject: Re[2]: afs server sizing
To: [EMAIL PROTECTED], [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED], [EMAIL PROTECTED], [EMAIL PROTECTED]
Message-Id: <[EMAIL PROTECTED]>
database machine configuration is a key performance factor. The latest AFS
releases are a lot more memory hungry than older releases; and even if
your cell has not grown much, chances are your AFS backup database
is a lot larger than it used to be. Slow database machines
will slow down even the speediest clients & file servers
(and *will* even slow down backups) so it's worth making sure your
database servers aren't overloaded, but are fast, endowed with more
than enough memory to avoid paging, don't do anything but DB service,
and & have plenty of fast disk for that.
Marcus,
I'm relatively new to the afs environment. Everything you outlined in your
message made sense, however I'm curious about your recommendation of having AFS
DB servers provide only DB services. What about having these do AFS file
services also? I recently raised this same question to Transarc, and their
response was "most sites run AFS file services on the DB systems as it is not
cost effective to buy a server license for just DB services". Cost is a factor
for us, but performance is paramount.
Troy Thompson
