Too much uptime !

Julian Field MailScanner at
Mon Oct 10 19:05:18 IST 2005

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High load average figures from "uptime" are not an indication at all 
that your system is overloaded. It gives the average number of processes 
in the run queue. If a process is waiting for disk, it adds 1. If a 
process is waiting for network response, it adds 1. It doesn't mean 
anything is overloaded at all.

A load average of 3 means there are an average of 3 processes waiting 
for cpu, disk or network. Since you have 4 CPUs then 1 of them is idle. 
A load of 12 to 15 on a hard-working single cpu system is perfectly 
common, it just means that all your system resources are being 
thoroughly used.

I usually recommend 5 children per CPU. So you should start by setting 
it to 20.

The Queue Scan Interval won't make any difference, I might remove it 
some time. It only affects the behaviour of the system when there are 
very few incoming messages. In all other situations it will process as 
many messages as it can without waiting for anything. It doesn't mean 
that MailScanner always waits 40 seconds to collect messages. If there 
are any messages waiting at all, then they are immediately processed. 
Leave it at 6.

With a load average of 3 on a box with 4 cpu's, you've wasted your money 
as at least 1 cpu isn't even doing anything. A load average of 30 or 40 
would mean your machine is working for its dinner.

Rabellino Sergio wrote:

> Dear list,
> i'm getting an high uptime on my mailscanner box, and this is a new 
> behaviour for me.
> The load average persist over 3.00 and my mail traffic is not so high.
> My actual config is
> MailScanner Rel4.45.4 - McAfee VirusScan - ClamAV cmd line - SA 3.0.4
> Max Children = 5
> Queue Scan Interval = 40
> I've changed The Scan Interval from 5 seconds to 40 and the max 
> children from 10 to 5, but without any significant change in the load.
> My Solaris 9 box is an V440 with 4GB of ram and 4 ultrasparc CPU.
> Where I need to investigate ? From a simple check, seems that 2 
> MailScanner processes are statically  in O-state and three are in 
> either R/S state: it's normal ?

- -- 
Julian Field
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