Chapter 10. Copy services 579
Step 3:
When the background copy completes, the MM/GM relationship transitions from the
InconsistentCopying state to the ConsistentSynchronized state.
Step 4:
a. When a MM/GM relationship is stopped in the ConsistentSynchronized state, the
MM/GM relationship enters the Idling state when you specify the -access option,
which enables write I/O on the auxiliary volume.
b. When a MM/GM relationship is stopped in the ConsistentSynchronized state without
an -access parameter, the auxiliary volumes remain read-only and the state of the
relationship changes to ConsistentStopped.
c. To enable write I/O on the auxiliary volume, when the MM/GM relationship is in the
ConsistentStopped state, issue the svctask stoprcrelationship command, which
specifies the -access option, and the MM/GM relationship enters the Idling state.
Step 5:
a. When a MM/GM relationship is started from the Idling state, you must specify the
-primary argument to set the copy direction. If no write I/O was performed (to the
master or auxiliary volume) while in the Idling state, the MM/GM relationship enters
the ConsistentSynchronized state.
b. If write I/O was performed to the master or auxiliary volume, the -force option must be
specified and the MM/GM relationship then enters the InconsistentCopying state
while the background copy is started. The background process copies only the data
that changed on the primary volume while the relationship was stopped.
Stop on Error
When a MM/GM relationship is stopped (intentionally, or because of an error), the state
changes. For example, the MM/GM relationships in the ConsistentSynchronized state enter
the ConsistentStopped state, and the MM/GM relationships in the InconsistentCopying state
enter the InconsistentStopped state.
If the connection is broken between the two systems that are in a partnership, all (intercluster)
MM/GM relationships enter a Disconnected state. For more information, see “Connected
versus disconnected” on page 579.
State overview
In the following sections, we provide an overview of the various MM/GM states.
Connected versus disconnected
Under certain error scenarios (for example, a power failure at one site that causes one
complete system to disappear), communications between two systems in an MM/GM
relationship can be lost. Alternatively, the fabric connection between the two systems might
fail, which leaves the two systems running but they cannot communicate with each other.
When the two systems can communicate, the systems and the relationships that spans them
are described as
connected. When they cannot communicate, the systems and the
relationships spanning them are described as
disconnected.
Common states: Stand-alone relationships and Consistency Groups share a common
configuration and state model. All MM/GM relationships in a Consistency Group have the
same state as the Consistency Group.
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