LVM2 introduces a new format for storing metadata on disk.
This new format is more efficient and resilient than the format the
original version of LVM used and offers the advanced user greater
flexibility and control.
The new format may be selected on the command line with -M2 or by
setting format = "lvm2" in the global section of lvm.conf.
Each physical volume in the same volume group must use the same format, but
different volume groups on a machine may use different formats
simultaneously: the tools can handle both formats.
Additional formats can be added as shared libraries.
Additional tools for manipulating the locations and sizes of metadata areas
will be written in due course. Use the verbose/debug options on the tools
to see where the metadata areas are placed.
-
- --metadatasize size
-
The approximate amount of space to be set aside for each metadata area.
(The size you specify may get rounded.)
-
- --metadatacopies copies
-
The number of metadata areas to set aside on each PV. Currently
this can be 0, 1 or 2.
If set to 2, two copies of the volume group metadata
are held on the PV, one at the front of the PV and one at the end.
If set to 1 (the default), one copy is kept at the front of the PV
(starting in the 5th sector).
If set to 0, no copies are kept on this PV - you might wish to use this
with VGs containing large numbers of PVs. But if you do this and
then later use vgsplit you must ensure that each VG is still going
to have a suitable number of copies of the metadata after the split!
-
- --restorefile file
-
In conjunction with --uuid, this extracts the location and size
of the data on the PV from the file (produced by vgcfgbackup)
and ensures that the metadata that the program produces is consistent
with the contents of the file i.e. the physical extents will be in
the same place and not get overwritten by new metadata. This provides
a mechanism to upgrade the metadata format or to add/remove metadata
areas. Use with care. See also vgconvert(8).
-
- --labelsector sector
-
By default the PV is labelled with an LVM2 identifier in its second
sector (sector 1). This lets you use a different sector near the
start of the disk (between 0 and 3 inclusive - see LABEL_SCAN_SECTORS
in the source). Use with care.
-
- --setphysicalvolumesize size
-
Overrides the automatically-detected size of the PV. Use with care.