HP-UX Reference (11i v1 05/09) - 1M System Administration Commands N-Z (vol 4)

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vgchange(1M) vgchange(1M)

Deactivate volume group /dev/vg03:

vgchange -a n /dev/vg03

Activate volume group /dev/vg03 without synchronizing extents that are not current on logical volumes

that have Mirror Write Cache turned on:

vgchange -a y -s /dev/vg03

Exclusive Activation

Set up volume group /dev/vg03 for use in a high availability cluster:

vgchange -a n /dev/vg03 # Deactivate volume group

vgchange -c y /dev/vg03 # Enable volume group for HA cluster

vgchange -c y -S y /dev/vg03 # Enable volume group for HA cluster

and mark as sharable

vgchange -a e /dev/vg03 # Activate volume group in exclusive mode

vgchange -a s /dev/vg03 # Activate volume group in shared mode

Activate all volume groups; activate those that are marked for membership in a high availability cluster in

shared mode:

vgchange -a y

Activate all volumes that are marked for membership in a high availability cluster in exclusive mode:

vgchange -a e

Cross Activation

Set up volume group /dev/sh_vg for use in a high availability cluster.

To make conﬁguration changes, to a volume group activated in shared mode, deactivate the volume group

by executing the following command on each cluster node except one:

vgchange -a n sh_vg

On the single node, where the volume group is active:

vgchange -a e -x sh_vg # Change mode to exclusive

vgchange -a s -x sh_vg # After configuration change, change

mode back to shared

WARNINGS

Ordinary Operation

In ordinary operation (i.e., without the optional high availability software), it is possible to activate a

volume group for read-write access from more than one physically connected system, leading to a high

potential for data corruption. Therefore, if access is desired from more than one system to a single volume

group, it is important that only one system activate the volume group for read-write access; the other sys-

tems can use read-only access. There is no problem if all systems activate the volume group for read-only

access.

Furthermore, volume group information is only read from the disks during volume group activation.

Dynamic changes to the volume group such as the following are not propagated to other systems sharing

the volume group:

Logical volume conﬁguration changes.

Changes to the status of the mirrored extents.

Bad-block relocation that occurs during write operations.

Because of these limitations, when sharing volume groups between systems it is recommended that logical

volumes be accessed only by one system at a time. If logical volumes need to be accessed simultaneously,

the logical volumes should not be mirrored and should not have bad-block relocation turned on, or all sys-

tems should use read-only access to the logical volumes.