HP StorageWorks XP Remote Web Console Software - Manual (Page 96)

96 ShadowImage for the XP128/XP1024/XP10000/XP12000
CAUTION: When the NOCOPY mode is selected, even if all the data in the S-VOL is copied to the T-VOL
by the on-demand copying process, the FlashCopy Mirror Version 2 does not automatically withdraw the
pair. So, when you selected NOCOPY mode, you must withdraw the pair by using FCWITHDR command.
For details about FCWITHDR command, see ” Withdrawing FlashCopy Mirror Version 2 Pairs: FCWITHDR ”
on page 114.
Volume Copying and Dataset Copying
FlashCopy Mirror Version 2 allows you to select the two types of copying. One type is the volume copying,
which copies the whole volume. Another type is the dataset copying, which copies only the specified copy
range (extent). While the volume copying establishes the relationship with the entire volume, the dataset
copying establishes the relationship only to the specified extent or extents. You can specify the multiple
extents.
To perform volume copying, the capacity of the copy source extent must be equal to or larger than the
capacity of the copy target extent. To perform dataset copying, the number of tracks of the copy source
extent and the copy target extent must be the same. Dataset copying allows you to establish up to 16
relationships to the copy source extent.
• FlashCopy Mirror Version 2 can perform dataset copying when:
• The position of the copy source extent is different from the position of the copy target extent.
• The volume of the copy source extent is different from the volume of the copy target extent.
• The copy source extent and the copy target extent are in the same volume, provided that they do not
overlap.
• The data in a single source extent is to be copied simultaneously to multiple target extents.
• Volume copying is also performed simultaneously in the same sourced volume.
• Two source extents overlap, or one of them is an inclusive part of the other (see
Figure 44 ),
provided that the number of overlapping extents in each overlapped area is not more than 16
extents.
Figure 44 Overlap of Copy Source Extents
• FlashCopy Mirror Version 2 cannot perform dataset copying when:
• Any one of the copy target extents is overlapping a copy source or target extent.
• A copy target extent that already has a relationship established is used to establish a new
relationship with a copy source or target extent that overlaps.