[TriLUG] System overload issues

[Bill Farrow]

On Fri, May 24, 2013 at 9:34 AM, Brian McCullough <bdmc at buadh-brath.com> wrote:
> Frequently during the day, the system will become ( or the web sites will become )
> non-responsive for periods ranging from one minute to well over an hour.

Have you thought about putting limits on processes to prevent them
from taking the system to it's knees ?  I would start by looking at
ulimit.  If you can prevent the system from becoming un-responsive,
then you can start investigating which process is going haywire and
hopefully fix it properly.

> Now, other things seem to be showing failure symtoms; for instance, bzip2, which
> compresses the MySQL database backup seems to take hours instead of minutes;

How big is the mysql dump file that is being compressed ?  Time how
long it takes when the system is running normally, and compare with
when the system is under load.

time bzip2 test-backup


I'm going to second Ron Kelley's suggestion that it might be a bad
hard drive.  Check dmesg and syslog for hard drive error messages.  I
had this happen on a RAID1 (mirror) system at work: it would normally
run fine but grind to a snail pace when it happened to read a bad
block on one of the drives.  I was disappointed that Linux software
RAID1 did not help in this situation.

Bill