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Sar

See Why is my system so slow? also.

Date: Thu, 08 Nov 2001 06:35:52 -0500
From: Tony Lawrence <tony@aplawrence.com>
Subject: Re: Server is slow

Edwin Ralphael wrote:
> 
> My customer Server had become very slow is there any solution?
> 
> The Configuration is:
> Compaq Proliant 1600
> P2 400
> 1GB Ram
> 18GB HDD
> running on SCO Openserver 5.0.5
> Network Speed is 100 MBps on a switch
> Application running is Oracle
> 
> but the users complaint that the server is really slow what can I do and
> what do I have to check?

You need to figure out WHY it is slow.

Your beginning tool for that is "sar"- enable it if it isn't already
enabled with 
/usr/lib/sa/sar_enable -y

Ignore the warning about rebooting- it is not necessary.

After a day or so, during which you are best occupied reading "man sar",
come back and run sar to see what is slowing your system down, and WHEN
it is slowing down.

sar -d will give you disk info
sar -r shows memory and swapping
just plain "sar" gives you cpu info.
sar -A | more gives you everything

If it is the cpu that is pegged busy, it *may* be a run away process
that is eating cpu cycles.  Do this:

for x in 1 2 3 4 5
do
ps -e | sort -r +2 | head -5
echo "==="
sleep 5
done

Look for a process who's time column has gone up by 4 or 5 seconds each
time- if you have something like that, that's your problem- you probably
need to kill it.

If sar -r shows low memory or (worse) swapping, go buy more memory (I
doubt it since you have 1GB already).   

If there are lots of memory pages available all day long, you may want 
to use some of that memory for disk buffers- see
SCo memory tuning


If your disk is  being hammered, move to a RAID configuration-

--
Tony Lawrence
SCO/Linux Support Tips, How-To's, Tests and more: 

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