You can use
the FlashCopy®, Metro Mirror, Global Mirror, and HyperSwap® Copy Services functions for the system across the hosts to
help simplify operations.
The following requirements and restrictions apply to Copy Services:
- If you require concurrent read/write access to both the source
and target volumes, be sure that the source volume is on a different
host than the target volume. If you initiate a copy operation from
a source volume to a target volume that is on the same host, you create
a target volume with the same identification as the source volume.
The host sees two identical volumes.
- When the copy operation creates the same identification for the
target volume as for the source volume, you cannot distinguish one
from the other. Therefore, you might not be able to access the original
data.
- The target volume and the source volume can be on the same
host system for a Copy Services operation only under the following
conditions:
- For the IBM AIX® operating
system, when the host is using a logical volume manager (LVM) with
the recreatevg command.
- For Hewlett-Packard (HP), when the host is using LVM with the vfchigid -f command.
- For the AIX and Oracle operating systems, when the host is not
using an LVM.
- For host systems that run the VERITAS Volume Manager, the system
sets a bit in the inquiry data. This bit enables the VERITAS Volume
Manager to distinguish between the source and target volume for those mapping states where the source and target volumes might be identical copies.
- For any host system, when the host system can distinguish between
a source and a target volume that has the same identification.