Is there is a way I can look at the high water mark for Temporary Storage usage in a CICS region?
The SYSVIEW CTEMPSTG display command will allow customers to identify the High Water Mark of Temporary Storage usage. The Pct Used and TSMAIN Storage fields should provide the information you are looking for.
Pct Used will be the percentage of auxiliary temporary storage used.
TSMain Storage will display the current amount of MAIN temporary storage in use, and the maximum amount of MAIN temporary storage (high water mark), that was used.