Virtual LVI volumes can be assigned to SIz pairs, provided that the T-VOL has the same capacity
as the S-VOL. If you need to perform Virtual LVI operations on an existing SIz S-VOL or T-VOL, you
must delete the pair first to return the volume to Simplex status.

Cache Residency Manager

Cache Residency Manager for Mainframe volumes can be assigned to SIz pairs, and Cache
Residency Manager for Mainframe operations can be performed on existing SIz S-VOLs and
T-VOLs.

CAUTION:

The performance in the V-Split or SP-Pend state is different depending on the value

of the system option mode 459 (ON or OFF, OFF by default) and whether the T-VOL or the volume
in a pool that is associated with the T-VOL is an external volume or an internal volume.

Table 5 The performance in the state of V-Split or SP-Pend is different depending on the value of
the system option mode 459 and the type of T-VOL.

PSUS(SP) or COPY(SP)

S-VOL*

System option mode 459

The pair status changes to Split after all
the differential data are copied to the
cache in the storage system.

Internal volume

OFF

External volume

The pair status changes to Split after all
the differential data are copied to the
cache in the storage system and
completed the destage in the external
storage system.

Internal volume

External volume

Volume Security

Volume Security operations do not directly affect SIz operations. Secure LDEVs can be assigned
to SIz pairs, and SIz volumes can be secured. A secure LDEV will accept SIz initial and update
copy operations. However, you cannot specify volumes that are selected as invalid T-VOLs for SIz
T-VOLs. When an S-VOL is secured by Volume Security, this setting does not apply to the
corresponding T-VOLs.

SIz T-VOLs cannot be accessed by any host except when the pair is split.

Virtual LVI