Performance Parameters

The following access method services parameters provide performance information. All these performance options are discussed in Optimizing VSAM Performance.

CONTROLINTERVALSIZE parameter—Specifies the control interval size for VSAM to use (instead of letting VSAM calculate the size).
The size of the control interval must be large enough to hold a data record of the maximum size specified in the RECORDSIZE parameter unless the data set was defined with the SPANNED parameter.

Specify the CONTROLINTERVALSIZE parameter for data sets that use shared resource buffering, so you know what control interval size to code on the BLDVRP macro.
SPANNED parameter—Specifies whether records can span control intervals. The SPANNED parameter is not permitted for fixed-length and variable-length RRDSs, and linear data sets.
SPEED|RECOVERY parameter—Specifies whether to preformat control areas during initial loading of a data set. See Using a Program to Load a Data Set.
VOLUMES parameter for the index component—Specifies whether to place the cluster's index on a separate volume from data.
FREESPACE parameter—Specifies the amount of free space to remain in the data component of a key-sequenced data set or variable-length RRDS's control intervals and control areas when the data records are loaded.