IBM Storwize V5010

586 Implementing the IBM Storwize V5000 Gen2 with IBM Spectrum Virtualize V8.1
Read/write access can be enabled as normal during resynchronization, rewinding the
secondary to the last consistent image. The hosts reading the secondary volume during
resynchronization will see data from the last consistent image. Also at the end of the cycle,
data may need to be cleaned from the change volume to the next FlashCopy map in the
cascade.
A change volume must be:
򐂰 Used by the relationship that owns it.
򐂰 In the same I/O group as the associated master or auxiliary volume.
򐂰 The same size as the associated master or auxiliary volume.
A change volume is owned and used by the associated Remote Copy relationship. Therefore,
it cannot be:
򐂰 Mapped to a host.
򐂰 Used as source or target of any FlashCopy maps.
򐂰 Part of any other relationship.
򐂰 A filesystem disk
Assigning a change volume to a relationship requires new FlashCopy mappings to be created
between the master or auxiliary volume and the associated change volume. Therefore, there
must be sufficient unallocated FlashCopy memory in the target I/O group or the command
fails.
10.9 Remote Copy commands
This section presents commands that need to be issued to create and operate remote copy
services.
10.9.1 Remote Copy process
The MM/GM process includes the following steps:
1. A system partnership is created between two IBM Storwize V5000 Gen2 systems or IBM
SAN Volume Controller (for intercluster MM/GM).
2. A MM/GM relationship is created between two volumes of the same size.
3. To manage multiple MM/GM relationships as one entity, the relationships can be made
part of a MM/GM Consistency Group to ensure data consistency across multiple MM/GM
relationships, or for ease of management.
Relationship is restarted
Relationship was stopped
(consistent_stopped or idling) and the
two copies are different
򐂰 Retain the secondary consistent copy
򐂰 Prepare for resynchronization
򐂰 Go to the consistent_copying state
򐂰 Replicate differences as and when possible
򐂰 Go back to consistent_synchronized when
complete
Note: Change volume should be created as thin provisioned, but in theory, can grow to
100%.
Event Expected behavior for the relationship