Hitachi Dynamic Link Manager Software Users Guide for AIX (6.6) (T5208-96010, April 2011)

4. HDLM Operation
180
4.1.6 Notes on Enabling Both Primary and Secondary Volumes to Be
Viewed From the Same Server
To enable both primary and secondary volumes to be viewed from the same server,
operate the disks according to the following steps:
1. Create a pair of the primary volume and the secondary volume (
paircreate).
2. Split the pair (
pairsplit).
3. Enable the secondary volume to be recognized as a volume group (
recreatevg).
When you execute the
recreatevg command, characteristics of the volume
group will be initialized. Therefore, change the characteristics of the volume
group (
chvg) as necessary.
4. Access the primary volume and the secondary volume.
5. Export the volume group, and then delete the volume information (
exportvg).
6. Re-synchronize the volume pair (
pairresync).
7. If there are several pairs of primary and secondary volumes, repeat the above
steps for each pair (step 2 to step 6).
4.1.7 Notes on an LVM Mirror Configuration
When an error (such as one that might occur in a LVM mirror configuration) is
detected and I/O access for a path in the Online(E) status continues, detection of errors
will continue. When the
-i parameter of the utility for setting the HDLM execution
environment ODM (
dlmodmset) is set to on, I/O access is suppressed until
troubleshooting measures are taken. This can shorten the time needed to deal with the
problem.
However, when this parameter is set to
on, I/O access to the path in the Online(E)
status will be suppressed, so I/O success will not automatically change the path to the
Online status. To recover the path, use an
online command or the auto failback
function.
For details about the
dlmodmset utility, see 7.7 dlmodmset Utility for Setting the
HDLM Execution Environment ODM.
4.1.8 Notes on When the OS Functionality in Not Available in a Boot
Disk Environment
When both of the following conditions exist, the reservation for the LU used for the
boot disk is not canceled:
• The reservation policy of the boot disk has been set to
PR_exclusive.
• The OS cannot start because OS functionality is not available due to a problem
such as an error occurring in all of the boot disk's paths.