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lvconvert

NAME

lvconvert - convert a logical volume from linear to mirror or snapshot

SYNOPSIS

lvconvert -m|--mirrors Mirrors [--mirrorlog {disk|core}] [--corelog] [-R|--regionsize MirrorLogRegionSize] [-A|--alloc AllocationPolicy] [-b|--background] [-f|--force] [-i|--interval Seconds] [-h|-?|--help] [--noudevsync] [-v|--verbose] [-y|--yes] [--version]
LogicalVolume[Path] [PhysicalVolume[Path][:PE[-PE]]...]

lvconvert -s|--snapshot [-c|--chunksize ChunkSize] [-h|-?|--help] [--noudevsync] [-v|--verbose] [-Z|--zero y|n] [--version]
OriginalLogicalVolume[Path] SnapshotLogicalVolume[Path]

lvconvert --repair [-h|-?|--help] [-v|--verbose] [--version] LogicalVolume[Path] [PhysicalVolume[Path]...]

DESCRIPTION

lvconvert will change a linear logical volume to a mirror logical volume or to a snapshot of linear volume and vice versa. It is also used to add and remove disk logs from mirror devices.
If the conversion requires allocation of physical extents (for example, when converting from linear to mirror) and you specify one or more PhysicalVolumes (optionally with ranges of physical extents), allocation of physical extents will be restricted to these physical extents. If the conversion frees physical extents (for example, when converting from a mirror to a linear, or reducing mirror legs) and you specify one or more PhysicalVolumes, the freed extents come first from the specified PhysicalVolumes.

OPTIONS

See lvm for common options.
Exactly one of --mirrors, --repair or --snapshot arguments required.

-m, --mirrors Mirrors

Specifies the degree of the mirror you wish to create. For example, "-m 1" would convert the original logical volume to a mirror volume with 2-sides; that is, a linear volume plus one copy.

--mirrorlog {disk|core}

Specifies the type of log to use. The default is disk, which is persistent and requires a small amount of storage space, usually on a separate device from the data being mirrored. Core may be useful for short-lived mirrors: It means the mirror is regenerated by copying the data from the first device again every time the device is activated - perhaps, for example, after every reboot.

--corelog

The optional argument "--corelog" is the same as specifying "--mirrorlog core".

-R, --regionsize MirrorLogRegionSize

A mirror is divided into regions of this size (in MB), and the mirror log uses this granularity to track which regions are in sync.

-b, --background

Run the daemon in the background.

-i, --interval Seconds

Report progress as a percentage at regular intervals.

--noudevsync

Disable udev synchronisation. The process will not wait for notification from udev. It will continue irrespective of any possible udev processing in the background. You should only use this if udev is not running or has rules that ignore the devices LVM2 creates.

--repair

Repair a mirror after suffering a disk failure. The mirror will be brought back into a consistent state. By default, the original number of mirrors will be restored if possible. Specify -y on the command line to skip the prompts. Use -f if you do not want any replacement. Additionally, you may use --use-policies to use the device replacement policy specified in lvm.conf, viz. activation/mirror_log_fault_policy or activation/mirror_device_fault_policy.

-s, --snapshot

Create a snapshot from existing logical volume using another existing logical volume as its origin.

-c, --chunksize ChunkSize

Power of 2 chunk size for the snapshot logical volume between 4k and 512k.

-Z, --zero y|n

Controls zeroing of the first KB of data in the snapshot. If the volume is read-only the snapshot will not be zeroed.

Examples

"lvconvert -m1 vg00/lvol1"
converts the linear logical volume "vg00/lvol1" to a two-way mirror logical volume.

"lvconvert --mirrorlog core vg00/lvol1"
converts a mirror with a disk log to a mirror with an in-memory log.

"lvconvert --mirrorlog disk vg00/lvol1"
converts a mirror with an in-memory log to a mirror with a disk log.

"lvconvert -m0 vg00/lvol1"
converts a mirror logical volume to a linear logical volume.

"lvconvert -s vg00/lvol1 vg00/lvol2"
converts logical volume "vg00/lvol2" to snapshot of original volume "vg00/lvol1"

"lvconvert -m1 vg00/lvol1 /dev/sda:0-15 /dev/sdb:0-15"
converts linear logical volume "vg00/lvol1" to a two-way mirror, using physical extents /dev/sda:0-15 and /dev/sdb:0-15 for allocation of new extents.

"lvconvert -m0 vg00/lvmirror1 /dev/sda
converts mirror logical volume "vg00/lvmirror1" to linear, freeing physical extents from /dev/sda.

SEE ALSO

lvm(8), vgcreate(8), lvremove(8), lvrename(8), lvextend(8), lvreduce(8), lvdisplay(8), lvscan(8)