Quickly Check for Disk Bottlenecks

Q: I think my disk might be causing performance problems in my environment. How can I quickly check?

A: The easiest way to see if your disks are causing performance problems is to look at read and write delays on each physical disk. This can be done as follows:

1. Start Performance Monitor.
2. Navigate to Monitoring Tools, Performance Monitor.
3. Click the Add button.
4. Navigate to the PhysicalDisk counter group and expand it.
5. Add the Avg. Disk sec/Read and Avg. Disk sec/Write counters for the disk instances you're concerned about, as the following figure shows.
   
6. Click OK.

Look at the values. Anything sustained above .030 (30 milliseconds) is typically a storage performance problem. (For high-performance storage it's typically 0.000.) Certainly when you start seeing .1, that's a huge performance impact that will affect all performance.