[webmin-l] High I/O usage issues which may be related to Usermin...

[Jesse C. S. <jsm...@ga...>]

Hello once again everyone.  Since the new school year started we have 
been noticing increasingly high I/O usage on our servers.  When I run 
the top command quite often you will see the WA status swing from really 
low up into the 70-80 even 90% range for up to a min and then drop 
again.  I spend a little time trying to track down the problem and have 
noticed the following:

When I/O is really high I always see the following line in "ps aux | 
grep D":
1229     14619  0.8  0.2  37272 16520 ?        D    14:43   0:00 
/usr/local/usermin-1.230/mailbox/delete_mail.cgi

(Note: User ID is normally not the same one when polled)

Sometimes I also see the index.cgi file too, but no where near as much 
as the above.

A coworker in our department had made mention that maybe whats happening 
has something do with the process that usermin uses to remove mail from 
a mailbox when its deleted.  Something about compacting the box during 
the delete instead of doing it like Thunderbird and waiting to compact 
until space can be saved.   I guess case being all the reading and 
rewriting required to removed the dead message from the box.

I don't recall having this problem that bad last year.  On occassion 
when almost everyone was logged in things would get a little screwy, but 
not like this.

General information about our config:
Server:
Processors: Dual Opteron 242's
Ram: 6Gig ECC DDR
HDs: 1.2 TB 3ware Raid Array
OS: Slamd 64 10.2b (Slackware more or less)
Kernel: 2.6.18
Usermin Version: 1.230 (This was happening in the last version too 
however.  I just upgraded two days ago to see if the problem went away)

Unfortunately dealing with I/O problems isn't my speciality so I could 
be barking up the wrong tree here.  Any suggestions would be greatly 
appriciated as always...
-Jesse
Gateway School District
Monroeville, PA