Hitachi ShadowImage for z/OS user guide (HIT9503-96007, October 2007)

ShadowImage for z/OS user guide 103
• Volume copying (See ”Volume Copying and Dataset Copying” on page 104)
• Dataset copying (See ”Volume Copying and Dataset Copying” on page 104)
• Relationship expansion (See ”Relationship Expansion” on page 106)
• Consistency Group (See ”Copying Data by Using Consistency Group” on page 106)
• Incremental FlashCopy (See ”Incremental FlashCopy Function” on page 107)
• Reverse Restore (See ”Reverse Restore Function” on page 108)
Establishing Multiple Relationships
Creating the multiple pairs from one extent is called “multiple relationship”. FlashCopy Mirror Version 2
allows you to create up to 16 pairs from one extent. The figure below illustrates the examples of multiple
relationships.
Figure 48 Examples of Multiple Relationships
Specifying COPY mode or NOCOPY mode
Before starting the copy operation, FlashCopy Mirror Version 2 allows you to select the mode to run the
copy operation between COPY mode and NOCOPY mode. When you do not select the mode, FlashCopy
Mirror Version 2 automatically selects COPY mode.
When you select COPY mode, FlashCopy Mirror Version 2 copies all the data in the S-VOL to the T-VOL.
This process is called “background copying”. FlashCopy Mirror Version 2 automatically withdraw the pair
when the background copying is complete. Note that when you select NOCOPY mode, FlashCopy Mirror
Version 2 omits the background copying process.
If there is a request for write operation to the space in the S-VOL from where the data is not yet copied or
a request for read/write operation to the space in the T-VOL to where the data is not yet copied, FlashCopy