High numbers on disk avwaits colum

[Juan M Leon]

Hello, I hope someone can help me regarding this issue I with one some disk.
I have L2000 class server with 11.00.
we moved the data disk from a jbod jamaica drives to an EMC disks.
We modified some kernel parameters to help the disks performance (HP recomendation).
Recommendations
dbc_max_pct= no greater than 15
ninode =1024
swapmem_on =1
timeslice 10
vx_ninode =nfile=51002
vx_noifree

After the changes were applied and the server was rebooted. it seems to be running ok however I noticed that the avwaits time is a larger number compared to avservice.
Bellow I added the sar -d 5 5 output.
I was under the assumption that the avwaits number higher thant the avservice is an indicator of problems. However I dont see anyy problems so far.
Can someone explain to me why I am seeing this numbers.


sar -d 5 5

Please see the attached txt file.

Thank you in advance for all your help.

[RAC_1]

Except on disk-c12t3d3, everything looks ok to me. This disk is busy all the time and has very high avwaits. What lies on this disk? (pvdisplay on disk will tell you lvol and then FS from LV)

Depending upon what you have on that disk, you may want to stripe/move/distribute the load on that disk. Also have a look at glance -i to know lvols with high i/os.

[Kevin Wright]

As stated analyze what lvols you have on the busy disks.. pvdisplay.

if you have glance, that can help as well. Try to separate busy lvols to different physical volumes.

[Juan M Leon]

Thank you for your suggestions, we end up moving some of the database tables from the most actives filesystems to the less active. Now the individual disk utilization has improved to average of 70%