Endevor utility C1BM5000 UNLOAD FULL taking long time

Products

• Endevor

Issue/Introduction

When running a full unload under C1BM5000 it takes 12 hours to complete. Options in use are:
UNLOAD FULL FROM ENV * SYS * TO DDN UNLOAD

Can Broadcom offer suggestions on how to achieve a full backup of Endevor in a quicker fashion?

Environment

All Supported Releases

Resolution

1. Putting the PDS into LLA for the duration of the unload would very likely help. Doing so requires privileges which may not be available to the job that runs the unload.

2. Converting PDS to PDSE would probably also improve performance. PDSE directories are cached in a PDSE-managed address space and the effect of this caching would be similar to putting a PDS into LLA. In addition, PDSE V2 performs better than PDSE V1.
In user environment which used PDS for DELTA & BASE libraries, the elapsed time was over 12 hours for FULL UNLOAD of all environments and systems. After conversion of libraries to PDSE V2, the elapsed time was significantly reduced to 38 minutes.


3. Apply the 2 new PTFs "PERFORMANCE ENHANCEMENT FOR UNLOAD". These will improve UNLOAD performance, but the gain depends on how inventory is defined.
In user testing with fixes applied, for one environment and system using a PDS delta library, a summary of the FULL UNLOAD job log shows:

• EXCP count goes down by 25% from 1623301 to 1623301
• Total CPU goes down by 36% from 306.78 to 195.67 seconds
• Elapsed time goes down by 29% from 5881.56 (1h28min) to 4152.48 seconds (1h09 min).

The CPU-to-elapsed-time ratio is 4.7%, i.e. 95% of the elapsed time is spent waiting, mostly for BLDL's.  The ratio is much higher for the UNLOAD jobs run internally on Broadcom's production Endevor inventories. One system has around 100K elements and the corresponding UNLOAD takes around 45 minutes, which is 30% shorter for 5 times more elements. In this setup, the delta library (PDSE V1) has 140K members. 

4. When the PDSE V2 FULL UNLOAD of all environments/systems in #2 was repeated with the new PTFs applied, the elapsed time was reduced from 38 minutes to 26.5 minutes i.e. a similar 30% reduction as observed in #3.

Additional Information

"PERFORMANCE ENHANCEMENT FOR UNLOAD" PTFs (the fix spans 2 FMIDs):
18.0: LU07611 and LU07612
18.1: LU07798 and LU07799
19.0: LU07622

NOTE: The suggested frequency is that a full backup be run weekly and incremental backups be run daily: Performance and Maintenance Best Practices
Other documentation and KB article references:
Unload, Reload, and Validate
Regular Endevor file maintenance can improve C1BM5000 UNLOAD performance