Quick Reference for Common Tuning Tips
This list focuses primarily, but not exclusively, on servers running Solaris 2. It should help you decide whether you have overloaded the disks, network, available RAM, or CPUs.
The system will usually have a disk bottleneck.
In nearly every case the most serious bottleneck is an overloaded or slow disk. Use iostat -xn 30  to look for disks that are more than 5 percent busy and have average response times of more than 30 ms. The response time is mislabeled svc_t; it is the time between a user process issuing a read and the read completing (for example), so it is often in the critical path for user response times. If many other processes are accessing one disk, a queue can form, and response times of ...