Monitor common storage at the system level and the address space level

Products

• SYSVIEW Performance Management

Issue/Introduction

How can I monitor common storage in a proactive fashion at both the system level and the address space level?

Resolution

These thresholds are defined in the MVSTHRSH member of the parmlib data set. The VARS display has a complete list of MVS monitoring variables. The following table provides a subset that pertains to common storage. Thresholds for several of these variables are defined in the default member, so it can be referenced for examples.

System-level thresholds	Description
STGCSA	CSA storage allocated
STGCSA%	CSA storage allocated pct
STGCSAC	CSA storage converted to SQA
STGCSAF	CSA storage free
STGCSAM	CSA storage max free block
STGCSAS	CSA storage size
STGECSA	E-CSA storage allocated
STGECSA%	E-CSA storage allocated pct
STGECSAC	E-CSA storage converted to E-SQA
STGECSAF	E-CSA storage free
STGECSAM	E-CSA storage max free block
STGECSAS	E-CSA storage size
STGSQA	SQA storage allocated
STGSQA%	SQA storage allocated pct
STGSQAF	SQA storage free
STGSQAS	SQA storage size
STGESQA	E-SQA storage allocated
STGESQA%	E-SQA storage allocated pct
STGESQAF	E-SQA storage free
STGESQAS	E-SQA storage size
Address space-level thresholds	Description
JOBCSA	CSA storage allocated
JOBECSA	E-CSA storage allocated
JOBSQA	SQA storage allocated
JOBESQA	E-SQA storage allocated

 

There are also online displays that show common storage usage statistics and ownership.

COMMON

The COMMON command displays both summary and detailed information about common storage from a system-level perspective. The top portion of the display contains summary statistics for SQA, CSA, E-SQA, and E-CSA. The bottom portion of the display shows the same numbers broken down by subpool and storage key. Line commands are available that list the individual pieces of storage that make up the totals.

VSMTRACK

The VSMTRACK command also displays summary and detailed information about common storage, but from an address space-level perspective. The top portion of this display contains system-level summary stats similar to the COMMON command, but the bottom portion of the display identifies the jobs that have allocated this storage.

Issuing VSMTRACK SUMMARY displays one row per job showing the total amount of common storage it has allocated. You may also notice that some Jobnames are highlighted; this is because they ended but the storage is still allocated, which could indicate an orphaned storage condition.

A row can then be selected to provide a detail display of the individual pieces of storage that make up the totals for that job.

By defining thresholds to proactively monitor common storage usage, and using the COMMON and VSMTRACK commands to investigate any alerts, an IPL may be avoided due to running out of common storage.