72 IBM System Storage Solutions for Smarter Systems
򐂰 Migrate several of the standard (fully provisioned) volumes to another extent pool using
the Easy Tier Manual Mode (Easy Tier manual migration of ESE volumes is not currently
supported).
򐂰 Delete several of the fully-provisioned FlashCopy target volumes from the extent pool.
򐂰 Delete several of the volumes from the extent pool.
If real space in a DS8000 extent pool is completely exhausted, read I/O will be allowed for
existing volumes, but any write to an ESE volume that requires allocation of a physical extent
will not be allowed.
Considerations for ESE volumes
Considerations for ESE volumes in the DS8000 are as follows:
򐂰 There are no performance implications for using DS8000 ESE volumes, compared with
standard DS8000 volumes.
򐂰 A FlashCopy source volume must be a standard volume (fully allocated.) ESE volumes
are not currently supported for use with FlashCopy.
򐂰 A FlashCopy target volume must be either a fully allocated standard volume or a thinly
provisioned Track Space Efficient (TSE) volume. Thin provisioning of TSE volumes is
discussed in “DS8000 Track Space Efficient (TSE) FlashCopy target volumes” on page 72.
򐂰 DS8000 does not currently support the use of ESE volumes as source or target volumes
for remote mirroring. Thinly provisioned Track Space Efficient (TSE) FlashCopy target
volumes are supported with remote mirroring as described in “DS8000 Track Space
Efficient (TSE) FlashCopy target volumes” on page 72.
򐂰 DS8000 currently supports ESE thin provisioning for FB (open systems) volumes. It does
not currently support ESE thin provisioning for Count Key Data (CKD) (mainframe z/OS)
volumes.
5.2.2 DS8000 Track Space Efficient (TSE) FlashCopy target volumes
Originally, FlashCopy target volumes were required to be physically allocated at the same
size as the source volumes, as shown in Figure 5-4. For a 10 GB source volume, a 10 GB
FlashCopy target was defined. This resulted in the allocation of a large amount of physical
capacity that was not actually needed.
Figure 5-3 Originally, the source volume and FlashCopy target volume were required to be physically
allocated at the same size
To alleviate the potential over-allocation associated with fully provisioned FlashCopy target
volumes, the DS8000 allows the creation of thinly provisioned FlashCopy target volumes
called Track Space Efficient (TSE) targets. TSE FlashCopy target volumes are supported for
both open systems FB volumes and mainframe CKD volumes.
Standard FlashCopy volume
10 GB logical
10 GB physical
Standard volume
10 GB logical
10 GB physical

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