Use sp_sysmon to determine whether data placement across physical devices is causing performance problems. Check the entire sp_sysmon output during tuning to verify how the changes affect all performance categories.
Pay special attention to the output associated with:
I/O device contentions
All-pages locked heap tables
Last page locks on heaps
Disk I/O management
You can also use Monitor Server or the monitoring tables to help identify problems.
See Monitoring Adaptive Server with sp_sysmon and Monitoring Tables, which are both part of the Performance and Tuning Series.
