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

Performing ShadowImage for z/OS Operations Using Storage Navigator 5-19
Hitachi ShadowImage™ for IBM
®
z/OS
®
User’s Guide
– T-VOL: The LDKC:CU:LDEV of the T-VOL.
Note: An LDEV number that ends with a “#” mark indicates that the
LDEV is an external volume (e.g. 00:00:01#). For details regarding the
external volumes, see the Universal Volume Manager User’s Guide.
– Emulation: The emulation type of the S-VOL and T-VOL.
– Capacity(Cyl): The number of cylinders assigned to the volume.
– CLPR(S): The cache logical partition of the S-VOL.
– CLPR(T): The cache logical partition of the T-VOL.
• The Copy Pace drop-down list allows you to select the copy pace (from
Slower, Medium, or Faster) for all the pairs that you are splitting.
Notes:
– When the Preview List already holds some Split Volume Pair operation
settings, and you specify a different copy pace for new pairs in the Split
Volume Pair dialog box, the copy pace for the existing Split Volume Pair
operation settings displayed in the Preview List will be also changed.
The latest copy pace specified in the Split Volume Pair dialog box is
always reflected to the storage system.
– If you specify Slower, the pace of copying will be slow, but you can
minimizes the impact of SIz operations on storage system I/O
performance. If you specify Faster, the copy operation completes as
quickly as possible, but it will cause a large impact on the I/O
operation.
• The Select Split Type drop-down list allows you to select the split type
(from Quick Split or Steady Split) for all the pairs that you are splitting.
The following table shows read/write operations from the host servers to
the volumes during the split pair operation.
Table 5-2 Operations from the Host Servers During the Split Pair
Operation
Operations Volumes Quick Split Steady Split
S-VOL
Both areas which are not copied and areas which are already copied can be read as usual.
Read
T-VOL
The areas which are already copied can be read as
usual.
If the host server tries to read the area which is not
copied yet, firstly ShadowImage for z/OS copies that
area from the S-VOL, and then the host server will read
the area after the copy operation completes. Therefore,
the result will be the same as when the host server
reads the area which is already copied.
Cannot be read. Read processing will
finish abnormally.
Write S-VOL
Write operation for the area which is already copied to the T-VOL is performed normally.
If the host server tries to write data to the area which is not copied yet, new data will be written
after the old data is copied to the T-VOL. S-VOL data during the split operation will therefore be
copied to the T-VOL for sure.