cf_mem_sz - CF memory configuration parameter

This parameter controls the total memory that is used by the cluster caching facility, also known as CF.

Configuration type
Database Manager
Applies to
Applies to a Db2® pureScale® instance only.
  • Database server with local and remote clients
Parameter type
Configurable offline
Default [range]
AUTOMATIC [32768 - 4 294 967 295]
Unit of measure
Pages (4 KB)
When allocated
When the CF is started
When freed
When the CF is stopped
When the default setting AUTOMATIC is applied, the amount of cluster caching facility memory is determined by querying the total memory that is available on the CF server. The parameter is then set to either an appropriate percentage of the total memory on the CF server, or the amount of free memory on the machine, whichever value is less. An appropriate percentage is typically 70% to 90% of the total memory available on the CF. Factors for consideration during AUTOMATIC computation also include:
  • If the CF and any Db2 members coexist. In this scenario, the automatic computation takes into account of whether INSTANCE_MEMORY is set to automatic or a fixed value.
  • If there are multiple instances on the same host