Performance of your server can be improved by architecting your cache wisely. Suggestions to keep in mind when architecting your cache:
Distribute the load
Use multiple proxy cache partitions
Use multiple disk drives
Use multiple disk controllers
Proper cache setup is critical to the performance of your Proxy Server. The most important rule to remember when laying out your proxy cache is to distribute the load. Caches should be set up with approximately 1 Gbyte per partition and should be spread across multiple disks and multiple disk controllers. This type of arrangement provides faster file creation and retrieval than is possible with a single, larger cache.