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HP Hitachi Dynamic Link Manager Software User Manual

Page 202

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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.