> -----Original Message-----
> From: João Luiz - Terra [mailto:[EMAIL PROTECTED]
> Sent: Monday, October 08, 2007 3:13 PM
> To: firstname.lastname@example.org
> Subject: Re: [vchkpw] qmail high performance
> Hi Nick.
> Thank you.
> When concurrent POP3 is low, the loadavg of my server is low too.
> My i/o is very high. Is normal?
> If any user to connect in POP3, Can he to start a attack to up my I/O?
> CPU states: cpu user nice system irq softirq iowait
> total 10,8% 0,0% 1,0% 0,0% 0,2% 84,8%
> cpu00 25,1% 0,0% 0,5% 0,0% 0,1% 74,0%
> cpu01 12,1% 0,0% 0,9% 0,0% 0,3% 86,4%
> cpu02 4,3% 0,0% 1,7% 0,0% 0,1% 87,8%
> cpu03 1,5% 0,0% 0,7% 0,0% 0,3% 91,2%
How many hard drives are in this server? Are they in RAID at all? It's
looking that most of your high load average is due to waiting on IO. This is
solved by adding more drives to increase available IO bandwidth. You should
become familiar with two utilities, vmstat and iostat. If you're using a
redhat derived linux, install the sysstat rpm to gain access to iostat.
Between these two utilities you should be able to figure out where your
problems are coming from and how to resolve them.