You can use the IBMFlashCopy, 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 IBMAIX 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.