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