Calculating MAXECSA values

HCL Workload Automation for Z allocates ECSA storage for job-tracking events in blocks of 1424 bytes. Each block is equivalent to 16 events. Examples of MAXECSA storage values gives examples of the storage needed for, the storage actually allocated, and the events accommodated for several maxecsa values. The number of events created for each job or started task in your environment is influenced by the definitions in the EWTROPTS initialization statement. Every job or started task creates a minimum of six events. If the job or started task generates output and PRINTEVENTS(ALL) or PRINTEVENTS(END) is specified, an event is created when each output group is purged. If STEPEVENTS(ALL) is specified, an event is created for every step in the job or started task.

If you want to calculate values that are not shown in Examples of MAXECSA storage values for a given MAXECSA value, use this method:
  • Space requested = MAXECSA * 1024
  • Blocks = space requested / 1424 (round down to a whole number)
  • Space allocated = blocks * 1424
  • Events accommodated = blocks * 16
Table 1. Examples of MAXECSA storage values
MAXECSA value Amount of MAXECSA space requested Blocks of ECSA space allocated (bytes) Number of events accommodated
0 0 0 (0) 0
4 4096 2 (2848) 32
8 8192 5 (7120) 80
16 16384 11 (15664) 176
36 36864 25 (35600) 400
72 73728 51 (72624) 816
100 102400 71 (101104) 1136
200 204800 143 (203632) 2288
400 409600 287 (408688) 4592
500 512000 359 (511216) 5744
Note:
  1. Allocate enough ECSA storage so that job-tracking events are not lost when the HCL Workload Automation for Z event-writer subtask is not active. When the event writer is active, the number of queued events in ECSA is almost always 0. Allocate enough ECSA for the maximum amount of time you expect the event writer to be inactive.

    For example, after the IPL of a z/OS system, job-tracking events can occur before the tracker address space has become active. If you expect a maximum of 50 events to occur during this time, you should set a MAXECSA value of 8, as shown in Examples of MAXECSA storage values. When the event writer becomes active, the queued events are processed and removed from ECSA.

    If events are lost, message EQQZ035E is stored to the message log. For a description of this message, see Messages and Codes.

  2. ECSA storage for job-tracking events is required only if the started task includes an event-writer subtask. On a controlling system, you can have one address space running only an event writer subtask, and another one running the controller functions and the remaining tracker functions. In this situation, you must specify a MAXECSA value of 0 for the subsystem that contains the controller functions.
  3. To submit only trackers that have OPCOPTS EWTRTASK(NO) set, the MAXECSA value must also be 0. Do not define subsystems for trackers that will never be started, because this causes waste of ECSA storage. Even if performance monitors might show that a tracker has more ECSA than the value specified by the MAXECSA parameter, this extra ECSA belongs to other subsystems, and the total amount of ECSA used by HCL Workload Automation for Z for trackers never exceeds the total number of subsystems defined multiplied by their MAXECSA value.
  4. All ECSA storage is allocated above the 16 MB line.