Hard drive performance question

[Dan Nelson]

In the last episode (Aug 05), Jason Lieurance said:
> I have FreeBSD 4.7 server running a qmail-imap-squirrelmail email
> server and a apache 1.3.27 web server hosting 6 virtual domains that
> don't get a lot of traffic.
> 
> Hardware is:
> 
> P3 933MHz CPU
> 512 DDR ram
> Fujitsu MAN3184MP 18.2 GB U160 10K rpm 8MB buffer 2.9 ms access Hard drive 
> Adaptec 29160LP U160 SCSI controller
> 
> When I run vmstat, I get:
> 
> procs      memory      page                    disks     faults      CPU
>  r b w     avm    fre  flt  re  pi  po  fr  sr da0 md0   in   sy  cs us sy id
>  0 14 0  184016  40900   26   0   0   0  31   0   0   0  245  839  28  1  1 98
>  0 14 0   86940  40896    7   0   0   0  15   0  12   0  242  115  21  0  0 99
>  0 14 0   81460  40896    6   0   0   0  12   0  10   0  239   98  18  0  0 100
>  0 14 0   85172  40896    7   0   0   0  15   0  14   0  243  116  21  0  1 99
>  0 14 0  190092  40896   32   0   0   0  37   0  10   0  250  220  35  0  0 100
> 
> I've read this is a disk access problem where process are waiting on
> the disk. As you can see this is a constant but I thought the disk
> system I have was sufficient. Any thoughts, analysis, or other is
> appreciated, thanks.

I see only 10-15 I/Os per second on your disk, which would overload a
floppy drive but nothing else.  What problem specifically are you
trying to fix?

-- 
	Dan Nelson
	dnelson at allantgroup.com