Multiple XBM subsystems on an MVS system

For example, you could set up separate XBM subsystems to manage IMS data and Db2 data. To accommodate a large quantity of data, you could also set up one XBM subsystem to handle one Db2 instance, and another to handle another Db2 instance.

For snapshot processing, you might need additional XBM subsystems when the following conditions exist:

• You are processing more than 2 GB of preimages from a single DBMS instance by using data space (DSP) cache.
• Other DBMS instances need additional DSP cache.

A DSP cache is limited to 2 GB in size. If you operate in 64-bit mode and require more than a 2-GB cache, use private virtual storage (PVS). A PVS cache can be up to 511 GB.

For snapshot processing, only one XBM subsystem registers the data set and that XBM subsystem sends data sharing registrations to all member XBM subsystems. When you have defined multiple XBM subsystems and need to stop them, you can stop the XBM subsystems in any order.