The SST ASP% threshold can be thought of as early warning. Whether your system has a single ASP or dozens of them, the result of exceeding an ASP’s % threshold will be messages to QSYSOPR and/or QSYSMSG (which is often a better choice). If a user ASP% threshold is crossed and even if it breaks 100%, there is no necessarily critical condition. It may simply take some actions to bring the used amount back down to a reasonable level and perhaps to reset conditions after an IPL at some later time.

But exceeding 100% of a user ASP will encroach on system ASP storage. The system ASP is more important to the system than user ASPs are. When user ASPs begin to overflow into the system ASP, risk increases.

QSTGLOWLMT is specific to the system ASP. It doesn’t matter if your system has only one or more ASPs, QSTGLOWLMT always relates to the system ASP.

It also relates to the QSTGLOWACN system value. When QSTGLOWLMT is triggered, the QSTGLOWACN directive is done. QSTGLOWACN specifies an action for the system to take. This might be merely sending a message, but it can be calling a program, dropping to restricted state or even powering down.

ASP% thresholds cause messages to be sent. They are “early warnings” that someone probably should start to do something. QSTGLOWLMT is “last resort”. Since no one managed to handle the ASP% messages in time, the system will take over and protect itself in the manner given by QSTGLOWACN.

Tom