Abstract
Certain defective PTFs can allow a Heap Segment Storage leak when Save While Active (SWA) is used. Heavy SWA usage can lead to the system running out of this resource, exposing performance problems or even a termination of the operating system.
Content
The following defective PTFs are involved:
7.3: MF70440 (or supersedes MF70600 or MF70677)
7.4: MF70546 (or supersede MF70674)
7.5: MF70552 (or supersede MF70675)
With one of those PTFs applied, each instance of Save While Active (SWA) that ends can leave 9 segments of Resident Heap allocated. While there are hundreds of thousands of these segments available to the OS, the allocation leak can accumulate quickly in environments that rely heavily on SWA. The eventual impact can involve performance problems, and potentially lead to a partition termination, when the heap storage is exhausted.
It is recommended to apply the fixing PTFs, especially if your environment uses SWA regularly.
Fixing PTFs (contain the fix for this issue and the other issues addressed by the earlier, now defective PTFs):
7.3: MF70736
7.4: MF70758
7.5: MF70757
Application options:
Temp apply the fixing PTF(s) – Pro: This is the easiest option. Con: This will push the defective PTF(s) to the A side. In general the systems should not run on A side, and if they do, it’s not usually for very long. So, there is limited risk of encountering the issue if you have to run on A side.
Perm apply the fixing PTF(s) – Pro: This will push the fixing code to the A and B side. This is a good option if you already have one of the defective PTFs applied permanently. Con: Requires an IPL to apply Perm.
Remove the defective PTF(s) and temp apply the fixing PTF(s) – Pro: This will not push the defective PTF(s) to the A side. Con: If one of the defective PTFs is already applied Perm, then this does not fix the A side. Again, there is limited risk of encountering the issue if you have to run on A side and one of the defective PTFs is applied Perm.
Service Keywords:
B6000305
B6005121 0002000A 00100013
vl10002203 rc29
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