For performance reasons the CA Top Secret security file should be spread across multiple volumes.
1. The CA Top Secret security file and backup security files should be kept on different volumes. They should be kept on separate volumes incase of drive failure you will loose both files.
2. Avoid putting multiple security files and/or backup security files for different systems on a single volume. You could loose multiple systems if that one drive fails.
3. If you have multiple systems that DONT share the security file, you should set SHRFILE(NO) in you TSS parm file. This can save you 30% of I/O to the security file because enqueing and dequeing of records are no longer being done.
4. Turn SECCACHE to ON. With the abundance of 31 bit storage, there is no reason not to have SECCACHE on. This functionality caches signons which is the most resource intensive security call. This will improve performance.
5. Your audit file should be moved a low I/O pack if you are doing heavy auditing.