High CSA usage after Common Services maintenance

Products

• Common Components and Services for z/OS

Issue/Introduction

After applying PTF LU18099 (CARS2602 maintenance level), systems may experience significantly increased CSA usage by the CAMASTER address space, sometimes exceeding 80% thresholds.

Cause

This issue is caused by PTF LU18099, which has since been marked as PE (Program Error). The PTF contains a defect where storage that should be allocated in ECSA is instead allocated in CSA during initialization.

Resolution

To resolve the increased CSA usage, customers must perform one of the following actions:

1.  Apply corrective PTF LU20327: This fix moves the allocated storage from CSA back to ECSA.

2.  Restore PTF LU18099: If the corrective fix is not yet available or cannot be applied, restoring the PE'd PTF LU18099 will revert the storage allocation behavior.

3. Check Article CAS9 is holding excessive amount of CSA (247616)

Note: Both courses of action require an IPL to successfully reclaim the CSA storage already allocated.

 

Additional Information

• One-time Allocation: The increased CSA usage is a one-time allocation that occurs during CAMASTER initialization. 
• Runtime Stability: CAMASTER's CSA usage will not continue to increase during system runtime.