Hitachi ShadowImage for IBM z/OS User"s Guide (T5213-96002, June 2007)

About ShadowImage™ for IBM
®
z/OS
®
Operations 2-5
Hitachi ShadowImage™ for IBM
®
z/OS
®
User’s Guide
Add Pair Operation
To create (add) an SIz pair, the volume, which will be the S-VOL, must be in
the simplex state. You may set reserve attribute on the T-VOL before adding it
to an SIz pair. You can also create a pair with an un-reserved simplex volume.
For detailed information about how to create SIz pairs, see section Adding
Pairs and Performing Pair Addition and Pair Splitting.
When you create a new volume pair, initial copy starts and all the data in the
S-VOL is copied to the T-VOL. Figure 2-2 shows the change of the status of a
pair from the start to end of the initial copy operation.
T-VOLS-VOL
Duplex
T-VOLS-VOL
Pending
Simplex
T-VOLS-VOL
Host
Initial Copy
I/O operation
: Duplex status
: Pending status
Lengend
: Simplex status
: Time flow
Figure 2-2 Adding a Pair (Initial Copy)
Before the initial copy operation, the status of a pair is Simplex. The status of
the pair is Pending while the initial copy operation is in progress. The status
changes to Duplex when the initial copy is complete.