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Commands Reference, Volume 5
unmirrorvg Command
Purpose
Removes the mirrors that exist on volume groups or
specified disks. This command only applies to AIX 4.2.1 or later.
Syntax
unmirrorvg [ -c Copies ] VolumeGroup [ PhysicalVolume .. . ]
Description
The unmirrorvg command unmirrors
all the logical volumes detected on a given volume group. This same functionality
may also be accomplished manually if you execute the rmlvcopy command for each individual logical volume in a volume group.
By default, unmirrorvg will
pick the set of mirrors to remove from a mirrored volume group. If you wish
to control which drives no longer are to contain mirrors, you must include
the list of disks in the input parameters, PhysicalVolume.
When the PhysicalVolume parameter
is listed in the command, this indicates that only the mirrors that exist
on this disk should be unmirrored. Mirrors that exist on other drives in the
volume group, but not listed in a user-provided disk list are left alone and
remain mirrored.
Notes:
- If LVM has not recognized that a disk has failed it is possible that LVM
will remove a different mirror. Therefore if you know that a disk has failed
and LVM does not show those disks as missing you should specify the failed
disks on the command line or you should use replacepv to
replace the disk or reducevg to remove the disk.
- If a logical volume copy spans more than one disk, the portion of the
logical volume copy that resides on a disk not listed by the user is also
removed.
- The unmirrorvg command is not allowed
on a snapshot volume group.
When unmirrorvg is executed,
the default COPIES value for each logical volume
becomes 1. If you wish to convert your volume group from triply mirrored to
doubly mirrored, use the -c option.
Note
To use this command, you must either have root user authority or be a member
of the system group.
Attention: The unmirrorvg command may take a significant
amount of time to complete because of complex error checking and the number
of logical volumes to unmirror in a volume group.
Y ou can use the System Management Interface Tool
(SMIT) to run this command. To use SMIT, enter:
smit unmirrorvg
Flag
-c Copies |
Specifies the minimum number of copies that each logical volume must
have after the unmirrorvg command has finished executing.
If you do not want all logical volumes to have the same number of copies,
then reduce the mirrors manually with the rmlvcopy command.
If this option is not used, the copies will default to 1. |
Examples
- To unmirror a triply mirrored volume group and leave two copies, enter:
unmirrorvg -c 2 workvg
The logical partitions in
the logical volumes held on workvg now have 2
copies.
- To get default unmirroring of rootvg, enter:
unmirrorvg rootvg
rootvg now has only 1
copy.
- To replace a bad disk drive in a mirrored volume group, enter:
unmirrorvg workvg hdisk7
reducevg workvg hdisk7
rmdev -l hdisk7 -d
replace the disk drive, let the drive be renamed hdisk7
extendvg workvg hdisk7
mirrorvg workvg
Note
By default in this example, mirrorvg will try to create 2 copies for logical volumes in workvg. It will try to create the new mirrors onto the replaced disk
drive. However, if the original system had been triply mirrored, there may
be no new mirrors created onto hdisk7, as other
copies may already exist for the logical volumes. This follows the default
behavior of unmirrorvg to reduce the mirror copy count
to 1.
Files
/usr/sbin |
Directory where the unmirrorvg command resides. |
Related Information
The mklvcopy command, mirrorvg command, syncvg command, reducevg command, extendvg command.
The Logical Volume Storage
Overview in AIX 5L Version 5.2 System Management Concepts: Operating System and Devices.
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