Restrictions on VIRTUAL(max)

The VIRTUAL(max) value on the FILESYSTYPE PARM('') keyword specifies the maximum amount of virtual memory (in megabytes) that file system data and meta data buffers should use. If you do not specifically set a value for VIRTUAL(max), the system assigns to max a default value that is equal to half the amount of real storage available to the system at initialization. (The sample BPXPRMxx member provided in SYS1.SAMPLIB uses this default). If you change the storage, consider beforehand how the change will affect your current system storage usage.

You should monitor the paging of your system. If paging is increasing, you might need to set a lower value on the VIRTUAL parameter to relieve the situation.

For more information about VIRTUAL(max) and other FILESYSTYPE PARM('') keywords, see the BPXPRMxx topic in z/OS MVS Initialization and Tuning Reference.