Expansion of a TDEV with active SnapVX sessions is available beginning with PowerMaxOS 5978, Solutions Enabler 9.0, Unisphere for PowerMax 9.0, and REST API 9.0. Both source and target devices can be expanded, and the functionality supports FBA and CKD devices.

SnapVX source devices may be expanded while maintaining the point-in-time image of existing targetless snapshots. Solutions Enabler and Unisphere outputs have fields to report if a device has been expanded since the snapshot was taken, and the device size at time of snapshot creation. The fields are shown in the following output example and in Figure 13.

The following is the output of the symsnapvx list –detail command in Solutions Enabler 9.0.

$ symsnapvx -sid <sid> -sg <sg_name> list -detail

Storage Group (SG) Name  : ODE_Prod_SG

SG's Symmetrix ID        : 000197800XYZ  (Microcode Version: 5978)

---------------------------------------------------------------------------------------

                                                         Snapshot     Total

Sym                     Flags                            Dev Size    Deltas  Non-Shared

Dev Snapshot Name Gen FLRG TSEB       Snapshot Timestamp (Tracks)   (Tracks)   (Tracks) 

--- ------------- --- --------- ------------------------ -------- ---------- ---------- 

 3B         Snap1   0 .... ..X. Fri Nov 17 12:05:01 2017   327690        452          0

 3C         Snap1   0 .... ..X. Fri Nov 17 12:05:01 2017   327690        869          0

 3D         Snap1   0 .... ..X. Fri Nov 17 12:05:01 2017   327690        784          0

 3E         Snap1   0 .... ..X. Fri Nov 17 12:05:01 2017   327690        142          0

                                                                  ---------- ----------

                                                                        2247          0

Flags:

 (F)ailed    : X = General Failure, . = No Failure

             : S = SRP Failure, R = RDP Failure

 (L)ink      : X = Link Exists, . = No Link Exists

 (R)estore   : X = Restore Active, . = No Restore Active

 (G)CM       : X = GCM, . = Non-GCM

 (T)ype      : Z = zDP snapshot, . = normal snapshot

 (S)ecured   : X = Secured, . = Not Secured

 (E)xpanded  : X = Source Device Expanded, . = Source Device Not Expanded

 (B)ackground: X = Background define in progress, . = No Background define

Figure 13.    SnapVX source volume display in Unisphere 9.0

Considerations for linked targets

• The snapshot device size must be considered during link operations.
• Target devices must be equal or larger capacity of the snapshot device size, not the size of the source device itself.
• Snapshot device size must also be considered during relink operations.

• For example, if a snapshot has an existing linked target of the same capacity, and then the source device is expanded, then a new snapshot is taken, attempt to relink to the new snapshot will be blocked.
• However, the target device can be expanded without being unlinked.

• Fully defined linked target devices in both copy and nocopy modes may be expanded.
• Restore from a snapshot that was created before a source device is expanded is allowed.

• Source TDEV size is not reduced.
• Data on the source TDEV that is beyond the size of the snapshot is deallocated during the restore operation.

• Device expansion is not supported with the following session types:

• Legacy TimeFinder Modes
• Devices in active Non-disruptive Migration (NDM) sessions
• Open Replicator Sessions (ORS)
• Parallel Clone
• VMware vSphere Virtual Volumes (vVols) with Replication
• FlashCopy or Remote Pair FlashCopy
• Devices involved in ProtectPoint sessions
• Internal and external RecoverPoint devices