ABCs of z/OS System Programming Volume 3 - IBM Redbooks

USEEAV(YES|NO)
YES This means that extended address volumes can be used to allocate new data sets
or to extend existing data sets to new volumes.
NO (Default) This means that SMS does not select any extended address volumes
during volume selection. Note that data sets might still exist on extended address
volumes in either the track-managed or cylinder-managed space of the volume.
Note: You can use the SETSMS command to change the setting of USEEAV without
having to re-IPL. This modified setting is in effect until the next IPL, when it reverts to the
value specified in the IGDSMSxx member of PARMLIB.
To make the setting change permanent, you must alter the value in SYS1.PARMLIB. The
syntax of the operator command is:
SETSMS USEEAV(YES|NO)
SMS requests will not use EAV volumes if the USEEAV setting in the IGDSMSxx parmlib
member is set to NO.
Specific allocation requests are failed. For non-specific allocation requests (UNIT=SYSDA),
EAV volumes are not selected. Messages indicating no space available are returned when
non-EAV volumes are not available.
For non-EAS eligible data sets, all volumes (EAV and non-EAV) are equally preferred (or they
have no preference). This is the same as today, with the exception that extended address
volumes are rejected when the USEEAV parmlib value is set to NO.
94 ABCs of z/OS System Programming Volume 3