HP StorageWorks XP24000/XP20000 for FlashCopy Mirroring Software User Guide (T5240-96012, May 2011)

Figure 15 On-demand Copying
As shown in “On-demand Copying” (page 33), the on-demand copying process is as follows:
1. From the host, there is a Write request to the space in the S-VOL from which the data is not
yet copied, or there is a Read or Write request to the space in the T-VOL to which the data is
not yet copied.
2. When a request as shown in “On-demand Copying” (page 33) is made to the space in the
S-VOL or T-VOL from which or to which the data is not yet copied, Version 2 performs
on-demand copying before the Read or Write operation. By on-demand copying, the data is
copied from the S-VOL to the T-VOL.
3. When on-demand copying is completed, the Read or Write operation is performed.
Copy Modes 33