IBM Storwize V5010 User Manual

Chapter 10. Copy services 489
򐂰 The source volume and target volume are available (almost) immediately following the
FlashCopy operation.
򐂰 The source and target volumes must be the same “virtual” size.
򐂰 The source and target volumes must be on the same IBM Storwize system.
򐂰 The source and target volumes do not need to be in the same I/O Group or storage pool.
򐂰 The storage pool extent sizes can differ between the source and target.
򐂰 The source volumes can have up to 256 target volumes (Multiple Target FlashCopy).
򐂰 The target volumes can be the source volumes for other FlashCopy relationships
(
cascaded FlashCopy).
򐂰 Consistency groups are supported to enable FlashCopy across multiple volumes at the
same time.
򐂰 Up to 255 FlashCopy consistency groups are supported per system.
򐂰 Up to 512 FlashCopy mappings can be placed in one consistency group.
򐂰 The target volume can be updated independently of the source volume.
򐂰 Bitmaps that are governing I/O redirection (I/O indirection layer) are maintained in both
node canisters of the IBM Storwize I/O Group to prevent a single point of failure.
򐂰 FlashCopy mapping and Consistency Groups can be automatically withdrawn after the
completion of the background copy.
򐂰 Thin-provisioned FlashCopy (or Snapshot in the graphical user interface (GUI)) use disk
space only when updates are made to the source or target data, and not for the entire
capacity of a volume copy.
򐂰 FlashCopy licensing is based on the virtual capacity of the source volumes.
򐂰 Incremental FlashCopy copies all of the data when you first start FlashCopy and then only
the changes when you stop and start FlashCopy mapping again. Incremental FlashCopy
can substantially reduce the time that is required to re-create an independent image.
򐂰 Reverse FlashCopy enables FlashCopy targets to become restore points for the source
without breaking the FlashCopy relationship, and without having to wait for the original
copy operation to complete.
򐂰 The maximum number of supported FlashCopy mappings is 4096 per clustered system.
򐂰 The size of the source and target volumes cannot be altered (increased or decreased)
while a FlashCopy mapping is defined.
10.1.8 Reverse FlashCopy
Reverse FlashCopy enables FlashCopy targets to become restore points for the source
without breaking the FlashCopy relationship, and without having to wait for the original copy
operation to complete. It supports multiple targets (up to 256) and therefore multiple rollback
points.
A key advantage of the IBM Spectrum Virtualize Multiple Target Reverse FlashCopy function
is that the reverse FlashCopy does not destroy the original target, which enables processes
that are using the target, such as a tape backup, to continue uninterrupted.
IBM Spectrum Virtualize also provides the ability to create an optional copy of the source
volume to be made before the reverse copy operation starts. This ability to restore back to the
original source data can be useful for diagnostic purposes.

IBM Storwize V5010 Specifications

General

Brand	IBM
Model	Storwize V5010
Category	Storage
Language	English