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

v
vgchange(1M) vgchange(1M)
NAME
vgchange - set LVM volume group availability
SYNOPSIS
Activate volume group
/usr/sbin/vgchange -a
availability [-l][-p
][-q quorum][-s][-P resync_daemon_count]
[vg_name ... ]
Assign to high availability cluster and mark volume group sharable
/usr/sbin/vgchange -c
cluster -S sharable vg_name
Change activation mode of sharable volume group
/usr/sbin/vgchange -a
availability -x {vg_name...}
Remarks
MC/ServiceGuard cluster operations require the installation of the optional MC/ServiceGuard software,
which is not included in the standard HP-UX operating system.
Mirrored disk operations require the installation of the optional HP MirrorDisk/UX software, which is not
included in the standard HP-UX operating system.
DESCRIPTION
The
vgchange command with the -a option activates or deactivates one or more volume groups.
When the -a option is used together with the -x option, the vgchange command allows cross-activation
of a sharable volume group to the desired activation mode in a high availability cluster.
The vgchange command with the -c option controls the membership of one or more volume groups in a
high availability cluster. The vgchange command with the -c and -S options control the membership of
a volume group and mark it sharable.
The vgchange command without the -P resync_daemon_count option (default) will spawn one
nomwcsyncd process for each
NOMWC/NONE volume group being activated. This may create a lot of
nomwcsyncd processes running concurrently when it activates a large number of NOMWC/NONE volume
groups and overload.
The -P resync_daemon_count option provides a way to control the number of concurrent nomwcsyncd
processes. The count is an advisory number and a different count might be chosen internally if load balance
or other reason is needed. When specified, there are up to resync_daemon_count
+1nomwcsyncd
processes; one of them is the controlling processing to spawn others.
-P 0 will use the system default
(currently defined to be 4).
vg_name must be defined as a volume group in the file /etc/lvmtab .Ifvg_name is omitted, all volume
groups defined in
/etc/lvmtab are affected, when the -x option is not specified.
High Availability Cluster Overview
Volume groups can be defined on disk volumes that are accessible by more than one system in a high avai-
lability cluster. This situation has a high potential for data corruption unless higher level cluster software
services are used to coordinate shared access to the same volume group by all systems.
A volume group can be marked as part of a cluster. When such a group is activated in exclusive mode, it
can be accessed for exclusive read-write activity by only one of the systems at a time; the other systems can
have read-only access to the data. When the volume group is marked as sharable, it may be activated in
shared mode for read-write access by all the nodes in the cluster.
The configuration of a shared volume group can be changed only if it is activated in exclusive mode. Cross-
activation between shared and exclusive modes of shared volume groups is possible with the -x option to
vgchange.
Options and Arguments
vgchange recognizes the following options and arguments:
vg_name The path name of a volume group.
-a availability Set volume group availability. availability can have one of the following values:
y Activate each specified volume group and all associated physical and logical
volumes for read-write access. If a volume group is marked as part of a high
HP-UX 11i Version 1: September 2005 − 1 − Hewlett-Packard Company Section 1M−−1063