Re: Load problem with ims 5.2

Don't rely on top for gauging how slow/fast your I/O is going. It's  
better to run a iostat -xzn 5 and look for service times on the disks  
the store resides on to be below 20ms. Over 20ms the mailstore starts  
hating life and chews on it's self.

Can you post the following from configutil:

service.imap.maxsessions
service.imap.maxthreads

Also, nab some pstacks of the IMAPD processes so we can see what  
they're spinning on.

Usually a corrupt database / index results in a crash, not a  
performance issue. Something else to check is, is the ims-ms queue  
building up? If it is that usually means the store is performing poorly.

Also, what do you have your dbtmpdir set to?

-Chris

On Oct 15, 2007, at 6:35 PM, Rich Bishop wrote:

> Hello,
>
> We're running IMS 5.2 (I know it's old!) on Solaris 8 and suddenly  
> seeing some major load issues. It's one of two mailstores running  
> on a Sunfire 280R with 6GB. We've been on this hardware for a  
> couple of years and never noticed any problems until a couple of  
> weeks ago.
>
> Suddenly on this one machine we see very high loads (up to 700).  
> imapd processes are always consuming most of the CPU in top, and  
> the activity is pretty evenly divided between user and kernel (ie.  
> no or minimal iowait). Here's a top snapshot - load is low right  
> now but it shows imapd chewing up all the cpu. At this time we had  
> only 700 imap connections.
>
>
>
> last pid:  9266;  load averages: 26.25, 26.14,  
> 44.50                                                               
> 21:29:56
> 86 processes:  78 sleeping, 6 running, 2 on cpu
> CPU states:  0.0% idle, 58.4% user, 41.6% kernel,  0.0% iowait,   
> 0.0% swap
> Memory: 6144M real, 596M swap in use, 4513M swap free
>
>  PID USERNAME THR PRI NICE  SIZE   RES STATE   TIME    CPU COMMAND
> 8248 mailsrv   33  53   -2  175M   43M run     3:06 51.89% imapd
> 8219 mailsrv   16  50   -2  184M   41M run     3:37 12.44% imapd
> 8231 mailsrv   28  50   -2  178M   42M run     3:58  8.79% imapd
> 8300 mailsrv   23  58    0   28M   21M run     0:42  3.59%  
> tcp_smtp_server
> 8230 mailsrv   30  59   -2  232M   41M sleep   3:50  2.84% imapd
> 23887 root      11  58    0  142M  141M sleep 105:58  0.97% bpbkar
> 8269 mailsrv   10  50   -2  181M   54M run     0:12  0.86% mshttpd
> 8272 mailsrv   13  59   -2  218M   61M sleep   0:23  0.59% mshttpd
>
> As this came on so suddenly without any configuration changes or  
> major addition of users, I was wondering if we have some corrupt  
> database / index somewhere, but I really have no idea where to  
> look. Any suggestions would greatly appreciated.
>
> Thanks,
>
> Rich