Greetings,
We're running a pair of 4100s (DU 3.2G) that handle the following
functions:
Node A: login server. (2 400MHZ CPU, 3 DE500 ethernet, 1GB RAM).
Most people who log in here run Pine or Elm for e-mail purposes, but
there's also some News and other traffic. It's running 20 nfsiods and
32 nfsds.
Node B: mail hub. (2 300MHZ CPU, 3 DE500 ethernet, 500MB RAM).
This node handles all SMTP, IMAP, and POP processing for the users
on node A, and NFS-serves a 16GB RAID 5 array to the login server
and multiple workstations scattered within a single building (all are on
10MB ethernet). This system also has a Prestoserve 8MB module
that enhances NFS on the mailspool disk. This system runs 15 nfsiods
and 64 nfsds.
MAXUSERS on both nodes is at 1024.
There's a dedicated 100MB duplexed link between these two nodes--
said link handles ONLY the NFS traffic between the two. Other systems
talk to these systems via other ethernet channels.
Other misc. nodes handle Web, administrative, printing, and other functions.
They're not really a factor in this situation.
When we peak out at 420-430 users on the login server (75% of
whom are running Pine and therefore accessing their inbox files via
NFS), mail performance drops off badly (1-2 minutes to open the
user's inbox) while other functions on the login server are okay. At
this same time, POP performance is still pretty good, and we
have other users accessing files on the mail server from other systems
(a secondary login server with 100+ users, for instance) so the mail
server itself doesn't seem to be saturated.
After all that, the questions are:
1) does anyone have any ideas regarding methods for improving
performance on the login server (i.e. faster access to the NFS-mounted
mail directories? We've experimented with hard vs. soft mounts (the
latter is preferred so the entire system doesn't hang when the mail
server goes away) and timeouts on the mount with some success.
Other ideas would be useful.
2) does anyone have a set of "preferred" or suggested sysconfig
parameters for either of these scenarios? Digital tell me that they're
working on recommended parameters for various types of servers,
but so far no data.
3) a side question: has anyone had problems with Digital UNIX 4.0a
on the 4100 series? At any rate, are there any known patches which
are required (or generally are considered a good idea) on this release?
We know about the ping patch already.
Many thanks to all...
Dick Joltes
Manager, UNIX Systems & Multiplatform Services
Harvard Arts & Sciences Computer Services
joltes_at_fas.harvard.edu
http://www.fas.harvard.edu/~joltes
voice: 617-495-9281 fax: 617-495-1210
Received on Tue Dec 03 1996 - 21:49:20 NZDT