ADSVS532 2561 MORE SPACE REQUIRED FOR DATA STUMP - INCREASE SYSTEM PARM VSSTUMPL

Products

• Disk Backup and Restore - MVS

Issue/Introduction

During backup of some VSAM datasets the following message is issued : 

ADSVS532 2561 MORE SPACE REQUIRED FOR DATA STUMP - INCREASE SYSTEM PARM VSSTUMPL BY 100%

How to bypass this warning and could this value cause a CPU and/or Memory consumption increase?

Resolution

The message is related to the private storage that Disk acquires internally, called the stump.  The stump area can be increased by changing the

SYSPARM VSSTUMPL

as the message

2561

indicates.  

The stump is like an internal work area and intended as a performance improvement for Disk. The product keeps track of internal work areas and control blocks which it had to construct and/or obtain in the stump.  It keeps those control blocks in the stump so that if it needs those control blocks again it can read them from memory instead of rebuilding them.  For example the Format 1 DSCB is kept in the stump so Disk only has to obtain it once, after that it just re-read it from memory.

 Increasing the stump will increase the memory used by the Disk jobs and it only increases the private storage in the Disk batch job while it is running.  When the Disk batch job ends the memory is released.