Siemens U3585-J-Z125-8-76 1 manual Monitored data on 3419/21 disk controllers under PCA, Pca

SM2 monitoring programs PCA

PCA

Monitored data on 3419/21 disk controllers under PCA

This monitoring program records monitored data on 3419/21 disk controllers managed by the PCA (Peripheral Cache Administrator) subsystem. It is used to record statistics on the ADM PFA cache areas (Administrator Controlled Performant File Access). The main purpose of the subsystem is to configure the cache integrated in the controller according to the particular needs of the user, achieving a higher I/O throughput rate or shorter I/O times. The monitored values recorded by the PCA monitoring program serve to evaluate the efficiency of the cache configuration and to provide pointers on how to improve the utili- zation of the cache.

Unlike other SM2 monitoring programs, these statistics are not processor-oriented, rather they relate globally to a particular controller. This fact should be taken into account particu- larly when interpreting monitored data. For example, high hit or miss rates for a disk device supported by the cache do not necessarily imply that these were triggered by the host running SM2. Also, this does not mean that the disk device listed was ever addressed by the SM2 host via the controller, or that the device has even been generated on this host. This information about the particular configuration should be obtained before SM2 is put to practical use, in other words before selecting controllers or caches, with the aid of PCA subsystem SHOW commands.

PERIODIC-TASK

Monitored data on tasks

This monitoring program records the most important utilization data for all tasks. Each user can himself/herself use the SELECT-PERIODIC-TASK-PARAMETER statement to specify the sort criterion and the output information for online output. The privileged statement SET-PERIODIC-TASK-PARAMETER is used to specify the tasks whose data is to be written to the SM2 output file. This prevents the SM2 output file from becoming too large. Nonprivileged users receive information only on those tasks that are under their user ID.

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