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

About ShadowImage™ for IBM
®
z/OS
®
Operations 2-3
Hitachi ShadowImage™ for IBM
®
z/OS
®
User’s Guide
You may operate SIz directly from the host and do not need to use the
Storage Navigator computer, if you use VOS3 DMFVSS, Business Continuity
Manager, IBM PPRC host software functions, or IBM DFSMSdss host software
functions.
Volume Pairs and Consistency Groups
ShadowImage for z/OS performs internal copy operations for logical volume
pairs established by the user. Therefore, you need at least two volumes to use
SIz, one for copy source (S-VOL), and another for copy target (T-VOL). Each
SIz pair consists of one S-VOL and up to three T-VOLs, which are located in
the same storage system.
The SIz S-VOLs are the source volumes which contain the original data. The
SIz T-VOLs are the target volumes which contain the backup data. Each T-VOL
must be paired with only one S-VOL. During normal SIz operations, the
S-VOLs remain available to all hosts at all times for read and write I/O
operations (except during reverse copy and quick restore operations).When
the pair status is Duplex and if the S-VOL is updated, the differential data
between S-VOL and T-VOL will be copied to the T-VOL regularly. However,
since SIz T-VOLs are updated asynchronously, the S-VOL and T-VOL of the
pair in Duplex status may not be identical. Remember that the T-VOLs become
available for host access only after a split operation has been performed.
Using Business Continuity Manager, you can define multiple SIz pairs as one
consistency group. If you define a consistency group, you can split all SIz pairs
in the group by using the At-Time Split function. For details about the At-Time
Split function, see section Split Pair Operation.
ShadowImage for z/OS Software
You can operate ShadowImage for z/OS by using the Storage Navigator
computer. The Storage Navigator computer can be attached to the USP V
storage systems via the TCP/IP local-area network (LAN). The Storage
Navigator computer communicates and exchanges data directly with the
service processor (SVP) of attached storage systems. You become able to
acquire the information of the structure or status of the storage system, or
issue commands to the storage system.