• When a DP-VOL has pages allocated to an S-VOL, used pool capacity is
temporarily larger than the actual capacity because pages must be
reallocated in the DP-VOL. Therefore, before creating the pair, make sure
of the following:
¢
DP-VOL pool capacity is sufficient.
¢
Pool-VOLs that are added to a pool are not blocked. If Pool-VOLs are
blocked, restore the volume status, and then create the pair.
• Regarding page and license capacity:
¢
If a pair does not include a DP-VOL, volume capacity is counted
toward TC license capacity. For a DP-VOL with the data direct
mapping attribute, volume capacity is counted toward TC license
capacity.
If a pair includes a DP-VOL, only the allocated page capacity of
volume capacity is counted toward TC license capacity.
If a DP-VOL and a non-DP-VOL are included in a pair, the page
capacity and/or license capacity counted in the P-VOL and the S-VOL
may be different. This applies even when both P-VOL and S-VOL
include DP-VOLs, because the page capacity of the P-VOL or the S-
VOL changes by a relocated pool or released page or other action.
For more information, see the Provisioning Guide for Hitachi Virtual Storage
Platform Gx00 and Fx00 Models.
LUN Manager
• LUN Manager operations do not affect TC operations.
• Volumes that are under secure ports and/or that are assigned to host
groups or iSCSI targets can also be assigned to TC pairs.
• Volumes that are assigned to TC pairs can also be assigned to secure
ports and host groups or iSCSI targets for LUN Manager.
• TC S-VOLs cannot be accessed by any UNIX/PC server host except when
the pair is split.
For more information, see the Provisioning Guide for Hitachi Virtual Storage
Platform Gx00 and Fx00 Models.
Performance Monitor
Performance Monitor software provides detailed information about I/O activity
and performance in the storage systems. Storage system usage and
performance data is collected and displayed by Performance Monitor. This
information helps you to:
• Identify the optimum timing for performing TC operations.
• Determine the best locations for the TC S-VOL (for example, parity
groups with less-frequently accessed volumes to avoid bottlenecks of
backend activity).
4-6
Sharing TrueCopy volumes
Hitachi TrueCopy® User Guide for Hitachi Virtual Storage Platform Gx00 and Fx00 Models
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