Path: utzoo!attcan!utgpu!news-server.csri.toronto.edu!clyde.concordia.ca!thunder.mcrcim.mcgill.edu!snorkelwacker.mit.edu!hsdndev!husc6!encore!gharel
From: gharel@encore.com (Guy Harel)
Newsgroups: comp.sys.encore
Subject: Re: Multimax thrashing
Message-ID: <130188@infocenter.encore.com>
Date: 21 Dec 90 22:57:23 GMT
References: <2166@sirius.ucs.adelaide.edu.au>
Organization: Encore Computer Corp, Fort Lauderdale, FL
Lines: 23

From article <2166@sirius.ucs.adelaide.edu.au>, by francis@cs.ua.oz.au (Francis Vaughan):
> |> Use 'sar -AO' to collect data. Trim down your disk buffers to a minimal.
> |> Scan and flush more aggressively to free up pages quickier. You should see
> |> a net difference.


My apology! I spent a month tuning on UMAX V, but none on UMAX 4.3. Really
tought that 'sar' asavailable on 4.3.  Its a great tool and much more 
professional that anything alike on BSD. I guess that system tuning and 
triming (to save on mem) could be equally performed on BSD using:

	- pstat, to check on kernel data structure usage or non-usage
	- vmstat, to check on memory consumption and paging load
	- systat (diskstat?) to check on disk cache hit ratios

Guidelines to save on mem:

	1- reduce kernel tables to a minimum (users,inodes,sem..)
	2- exercise various 'flush' water marks and scan rates
	(this is more for smoothing off trashing effects)
	3- reduce cache size for disk to an aceptable minimum

Have fun (if you can afford it..)