HP-UX Reference (11i v1 00/12) - 1M System Administration Commands N-Z (vol 4)

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STANDARD Printed by: Nora Chuang [nchuang] STANDARD

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vgchange(1M) vgchange(1M)

vgchange -a y -s /dev/vg03

Exclusive Activation

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

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 availabilitycluster in

exclusive mode:

vgchange -a y

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

vgchange -a e

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.