Examine disk statistics by using performance counters that
are available in the Performance Monitor.
Procedure
- Start the Performance Monitor.
From a command
prompt, enter: perfmon
.
- Create a Data Collector Set to collect data about disks.
Select the following performance counters from the
Physical
Disk category:
- Avg. Disk Sec./Transfer
- Avg. Disk Queue Length
- Avg Disk Bytes/Transfer
- Disk Bytes/sec
- Split IO/sec
- Run the perfmon tool while you are experiencing
the performance problem. Compare the results with the guidance in
the following table.
Performance counter |
Guidance |
Physical Disk: Avg. Disk Sec./Transfer |
Values less than 25 ms are good. |
Physical Disk: Avg Disk Queue Length |
A value that is 2 or 3 times the number of disks
in the array is optimal. |
Physical Disk: Avg Disk Bytes/Transfer |
The goal is that the stripe size for the array
is at least the average of this counter. |
Physical Disk: Disk Bytes/sec |
Optimal result is that the sum of values for
all disks that are attached to a single controller is less than 70%
of the theoretical throughput. |
Physical Disk: Split IO/sec |
A nonzero value for this counter indicates possible
disk fragmentation. |