Multiple active databases in a Db2 pureScale environment

Outside of a Db2 pureScale environment, the maximum number of databases that can be active at any given time is 255. However, in a Db2 pureScale environment, the maximum number of databases that can be active at any given time is 200.

The default maximum number of active databases in a Db2 pureScale is 32. This is also the default for Db2 Enterprise Server Edition and partitioned database environments.

To have multiple active databases in a Db2 pureScale environment, see the configuration parameter changes outlined in CF memory parameter configuration.

To change the number of active databases in a Db2 pureScale environment, you can modify the numdb configuration parameter, and the change comes into effect after the next global restart.

In addition to the numdb limit in a Db2 pureScale environment, there is a maximum number of database activations across all members in an instance. This maximum number is 512 database activations. As an example, if each member in a four member Db2 pureScale environment activated 200 databases, that is a total of 800 database member activations. Since 800 database activations exceeds the maximum upper limit, an error is returned.

In a multiple database environment, if member crash recovery (MCR) is required, the number of databases that will be recovered in parallel on each member is set by the value of the numdb configuration parameter or the DB2_MCR_RECOVERY_PARALLELISM_CAP registry variable, whichever value is smaller.