From: halvard@trd.sdata.no (Halvard Halvorsen)
Subject: Re: Kernel Config -- Can maxusers be too big?
Organization: Skrivervik Data A/S
Date: Wed, 22 Jul 92 14:30:12 GMT

from the 4.1.2 release manuals - chapter 8.3 :

maximum MAXUSERS values :

arch	mem<64mb	128mb		640mb		2.5gb

sun4	225		225		NA		NA
sun4c	225		225		NA		NA
sun4m	185		180		155		45

well it clearly says MAXUSERS <= 225 for sun4 - so you are clearly running
an 'unsupported configuration' ...




In article <14emaeINNd8b@early-bird.think.com>, barmar@think.com (Barry Margolin) writes:
|> In article <1992Jul19.160905.11322@kodak.kodak.com> dennett@sunshine.Kodak.COM (Charlie Dennett) writes:
|> >Can the maxusers parameter in the kernel config file be so big that
|> >performance is affected?  Now, I have seen it where it was too big
|> >and the kernel would not boot because there was not enough memory.
|> >However, assuming memory is sufficient, can a large maxusers actually
|> >hurt performnce?
|> 
|> Most (all?) of the tables whose sizes are derived from maxusers are wired
|> in memory.  Therefore, this memory is not available for use as paging
|> space.  If you increase maxusers enough that the working set often doesn't
|> fit in memory, you'll page more.  This will slow the system down (how much
|> depends on the difference between the working set and available memory).
|> 
|> >  (the target of my attack is a 4/490 running 4.1.1 with
|> >128 meg of memory.  It is a major server --  18 spindles and 16+ gig --
|> >for both disks and cpu cycles and also supports a half dozen or so
|> >Xterminals.  Maxusers was at 128.  I tried raising it to 256.  It booted
|> >fine.  Pstat -T told be the max number of files was perposterous at
|> >over 14000.  What does pstat consider non perposterous?  It's running
|> >at 256 now.  We'll see what happens when the users start wailing on it
|> >Monday.)
|> 
|> Pstat considers nproc or nfiles more than 10,000 to be preposterous.  I
|> don't think it's intended to be a judgement about your configuration
|> decisions, but a sanity check; unexpectedly large values could be the
|> result of /vmunix not being the kernel you booted, so it's looking in the
|> wrong place for the value.
|> 
|> >Side issue:  As you may be able to tell by this posting and a couple
|> >of my previous ones, in case you noticed, I am trying to teach myself
|> >and to understand performance issues.  Is this group a reasonable
|> >place to discuss performance issues and tuning?  If not, what would
|> >be an appropriate place?
|> 
|> This is probably a good place, as would be comp.unix.large.  Also, there
|> are some good books, such as "System Performance Tuning" by Mike Loukides,
|> published by O'Reilly & Associates (they have lots of other good books for
|> Unix users and administrators).
|> -- 
|> Barry Margolin
|> System Manager, Thinking Machines Corp.
|> 
|> barmar@think.com          {uunet,harvard}!think!barmar

-- 

    0  	   halvard halvorsen - systems consultant - Skrivervik Data A/S
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