Hitachi ShadowImage for z/OS user guide (HIT9503-96004, June 2006)

86 ShadowImage for the XP1024/XP128/XP12000/XP10000
T-VOL where the T-VOL (the virtual or physical copy of the S-VOL) is available for both read and write
operations.
When you establish a relationship for an ShadowImage - FlashCopy pair, you can specify a range of data
to be copied, which is called the “extent.” When the extent data copy is complete, the relationship ends
automatically.
You can establish an ShadowImage - FlashCopy pair not only for SI390 simplex volumes, but also for
SI390 S-VOL or T-VOL in the split or duplex status.
• When the SSID boundary is 64-LDEV, S-VOL and T-VOL must be established in the same CU image and
SSID.
• When a relationship is established and the SSID boundary is changed from 256-LDEV to 64-LDEV, the
SSIDs for T-VOL and S-VOL become different. Because of this condition, the relationship cannot be
deleted from the host. In this case, you should delete the relationship from SI390 on the Remote
Console PC.
ShadowImage - FlashCopy Pair Status
The following figure illustrates the pair status transition and the relationship between the pair status and the
ShadowImage - FlashCopy operations.
Figure 41 ShadowImage - FlashCopy pair status transition
NOTE: When the extent data copy fails, the ShadowImage - FlashCopy relationship ends automatically
(the status becomes simplex) and the T-VOL is blocked.
Table 32 Requirements for ShadowImage - FlashCopy
Item Requirement
Controller emulation type I-2105
SSID boundary setting 256-LDEV (The SSID boundary of IBM ESS is 256-LDEV.)
Available volume FlashCopy Mirror can use the volume whose CU:LDEV
(control unit image: logical device ID) is between 00:00
and 3F:FF.