WebSphere Application Server for z/OS and OS/390 produces
a puzzling number of System Management server regions (BBOSMSS address
spaces) on idle systems. Customers observe that a new BBOSMSS server
starts up once every hour, lasts for 20 minutes and then terminates. This
occurs for as long as WebSphere is active on the system even though it is
idle.
These BBOSMSS server regions are created to perform Stateful Bean Table
maintenance. Environment variable BEAN_DELETE_SLEEP_TIME controls the
interval between Stateful Bean Table cleanups. The default is 4200 seconds
or 70 minutes. On an idle WebSphere system the BBOSMSS server region does
the Stateful Bean Table maintenance and then waits for more work. It is
terminated by WLM after 20 minutes. When the next Stateful Bean Table
maintenance is scheduled a new BBOSMSS is created to perform the table
maintenance. It then goes idle and is terminated after 20 minutes. This
cycle repeats over and over.
Environment variable MIN_SRS=1 for the Systems Management control
region can be used to ensure the BBOSMSS server region will not be shut
down. There will always be at least one SM server region available to
clear the Stateful Bean Session table. This avoids the periodic appearance
and disappearance of SM server regions on a totally idle system. Note also
that the BBOSMS control region does not stop and restart, only the System
Management server region BBOSMSS.
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