Why is the server bottleneck?

[Yvonne Chan]

Why is my device is always busy? What was the problem?
vmstat -t 1 -> c7t0d0 xfer/sec 277
iostat -t 1 -> c7t0d0 bps 18678
sar -du 1 99 -> c7t0d0 %busy 90-100%
top -> CPU load around 1-2
Why is the bottleneck?

[T G Manikandan]

Hello,
Just check the file system on c7t0d0.
Do you have any application related files on that specific disk/filesystem.ie.like oracle datafiles.
When your sar -d ouput is 90-100% over a longer period of time,examine the application that filesystem.Distribute your application files so that the I/O on that disk is reduced.
For example assume that there are datafiles and logfiles of Oracle in particular disk.When there is a large transaction going in the database the I/O load is higher.

Thanks

[John Carr_2]

Hi

you can check what processes are being run on the disk

fuser -u /dev/dsk/c7t0d0

John.

[S.K. Chan]

I would start by running glance and try to find out what process is doing the read/write which causes the heavy IO load you're seeing. Run glance with "-h"
# glance -h
===> In the main glance window you'll see a selection of command menu.
===> Take a look at ..
g- process list
B- global waits
Y- global system call
===> To get back to the main glance window which display these command menu enter "?".

[Tom Geudens]

Hi,
You can use the glance "IO by disk" and then select your specific disk to see which filesystems are causing your bottleneck ...

Hope this helps,
Tom