Group buffer pool monitoring with the coupling facility activity report of RMF
You can use RMF coupling facility structure reports to monitor group buffer pools.
The figure below shows a portion of an example report.
A value for CHNGD ( B ) is the percentage of all accesses that were supposed to be done synchronously that had to be done asynchronously. The NO SCH field ( A ) indicates the amount of time that requests were queued because of a lack of subchannel resources. If the value in B is over 10% or so, and A contains a non-zero value, your configuration might not have enough subchannels to handle your systems' workload.
STRUCTURE NAME = DSNDB0A_GBP8 TYPE = CACHE
# REQ -------------- REQUESTS ------------- -------------- DELAYED REQUESTS -------------
SYSTEM TOTAL # % OF -SERV TIME(MIC)- REASON # % OF ---- AVG TIME(MIC) -----
NAME AVG/SEC REQ ALL AVG STD_DEV REQ REQ /DEL STD_DEV /ALL
STLABC2 66662 SYNC 61K 43.2% 107.7 32.5 A
370.3 ASYNC 5677 4.0% 602.8 419.8 NO SCH 0 0.0% 0.0 0.0 0.0
B CHNGD 0 0.0% INCLUDED IN ASYNC
DUMP 0 0.0% 0.0 0.0