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Long WAIT times ??

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Roomer

Technical User
Oct 1, 2001
100
GB
My system seems to slow down at certain times during the day.

In order to ascertain why, I have run the 'topas' program.
It seems that the WAIT times are fairly high..

What can I do to resolve this issue? What normally causes the system to have long wait times?

thanks...
 
Do you have a application which runs at this time which causes a lot of disk I/O? We found DB2 particularly hungry when running large queries, due to large volumes of disk paging going on.

Solution? Disk striping? More RAM? How much RAM do you have free? Run the script posted elsewhere on this site to see how much you are using. IBM Certified Specialist - MQSeries
 
You need to find out why you wait times are so high. It is most likely to be disk I/O. This could be caused by paging or just the amount of work being run.

Run vmstat 2 120 > /tmp/vmstat.out and
iostat 2 120 > /tmp/iostat.out at the same time

during the busy time and post the results back. What sort of disks are you using ?
are you mirroring ?
are you stripping LVs ?





 
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