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Going forward, we would like to allow users to specify the total number of metadatacopies in a VG rather than on a per-PV basis. In order to facilitate that, introduce --pvmetadatacopes to replace --metadatacopies everywhere. We still allow --metadatacopies for pv commands, but require --pvmetadatacopies for vg commands. Eventually we will introduce --vgmetadatacopies. Once we do that, we should either deprecate --metadatacopies or make it a synonym based on the command (pvmetadatacopies for pv commands, and vgmetadatacopies for vg commands). The latter option would likely just require a simple 'strncpy' check against cmd->command->name to qualify the merge_synonym call. Update nightly tests to cover the pvmetadatacopies synonym. Note that this patch is the result of an eariler review comment for the implicit pvcreate patches. Should apply cleanly on top of the implicit pvcreate patches (I applied after patch 10/10 in that series). NOTE: This patch will require --pvmetadatacopies for vgconvert as --metadatacopies is no longer accepted.
162 lines
6.1 KiB
Groff
162 lines
6.1 KiB
Groff
.TH PVCREATE 8 "LVM TOOLS #VERSION#" "Sistina Software UK" \" -*- nroff -*-
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.SH NAME
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pvcreate \- initialize a disk or partition for use by LVM
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.SH SYNOPSIS
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.B pvcreate
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.RB [ \-d | \-\-debug ]
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.RB [ \-f [ f ]| \-\-force " [" \-\-force ]]
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.RB [ \-y | \-\-yes ]
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.RB [ \-h | \-\-help ]
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.RB [ \-t | \-\-test ]
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.RB [ \-v | \-\-verbose ]
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.RB [ \-\-labelsector ]
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.RB [ \-M | \-\-metadatatype type ]
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.RB [ \-\-[pv]metadatacopies #copies ]
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.RB [ \-\-metadatasize size ]
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.RB [ \-\-dataalignment alignment ]
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.RB [ \-\-dataalignmentoffset alignment_offset ]
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.RB [ \-\-restorefile file ]
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.RB [ \-\-setphysicalvolumesize size ]
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.RB [ \-u | \-\-uuid uuid ]
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.RB [ \-\-version ]
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.RB [ \-Z | \-\-zero y|n ]
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.IR PhysicalVolume " [" PhysicalVolume ...]
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.SH DESCRIPTION
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.B pvcreate
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initializes
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.I PhysicalVolume
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for later use by the Logical Volume Manager (LVM). Each
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.I PhysicalVolume
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can be a disk partition, whole disk, meta device, or loopback file.
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For DOS disk partitions, the partition id should be set to 0x8e using
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.BR fdisk "(8), " cfdisk "(8), "
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or a equivalent. For
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.B whole disk devices only
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the partition table must be erased, which will effectively destroy all
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data on that disk. This can be done by zeroing the first sector with:
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.sp
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.BI "dd if=/dev/zero of=" PhysicalVolume " bs=512 count=1"
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.sp
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Continue with
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.BR vgcreate (8)
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to create a new volume group on
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.IR PhysicalVolume ,
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or
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.BR vgextend (8)
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to add
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.I PhysicalVolume
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to an existing volume group.
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.SH OPTIONS
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See \fBlvm\fP(8) for common options.
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.TP
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.BR \-f ", " \-\-force
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Force the creation without any confirmation. You can not recreate
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(reinitialize) a physical volume belonging to an existing volume group.
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In an emergency you can override this behaviour with -ff.
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.TP
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.BR \-u ", " \-\-uuid " uuid"
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Specify the uuid for the device.
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Without this option, \fBpvcreate\fP generates a random uuid.
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All of your physical volumes must have unique uuids.
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You need to use this option before restoring a backup of LVM metadata
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onto a replacement device - see \fBvgcfgrestore\fP(8).
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.TP
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.BR \-y ", " \-\-yes
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Answer yes to all questions.
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.TP
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.BR \-Z ", " \-\-zero " y|n"
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Whether or not the first 4 sectors (2048 bytes) of the device should be
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wiped.
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If this option is not given, the
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default is to wipe these sectors unless either or both of the --restorefile
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or --uuid options were specified.
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.SH NEW METADATA OPTIONS
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LVM2 introduces a new format for storing metadata on disk.
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This new format is more efficient and resilient than the format the
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original version of LVM used and offers the advanced user greater
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flexibility and control.
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.sp
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The new format may be selected on the command line with \fB-M2\fP or by
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setting \fBformat = "lvm2"\fP in the \fBglobal\fP section of \fBlvm.conf\fP.
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Each physical volume in the same volume group must use the same format, but
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different volume groups on a machine may use different formats
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simultaneously: the tools can handle both formats.
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Additional formats can be added as shared libraries.
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.sp
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Additional tools for manipulating the locations and sizes of metadata areas
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will be written in due course. Use the verbose/debug options on the tools
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to see where the metadata areas are placed.
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.TP
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.BR \-\-metadatasize " size"
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The approximate amount of space to be set aside for each metadata area.
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(The size you specify may get rounded.)
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.TP
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.BR \-\-dataalignment " alignment"
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Align the start of the data to a multiple of this number.
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You should also specify an appropriate \fBPhysicalExtentSize\fP when creating
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the Volume Group with \fBvgcreate\fP.
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.sp
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To see the location of the first Physical Extent of an existing Physical Volume
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use \fBpvs -o +pe_start\fP . It will be a multiple of the requested
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\fBalignment\fP. In addition it may be shifted by \fBalignment_offset\fP from
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\fBdata_alignment_offset_detection\fP (if enabled in \fBlvm.conf\fP) or
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\fB--dataalignmentoffset\fP.
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.TP
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.BR \-\-dataalignmentoffset " alignment_offset"
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Shift the start of the data area by this additional \fBalignment_offset\fP.
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.TP
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.BR \-\-[pv]metadatacopies " copies"
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The number of metadata areas to set aside on each PV. Currently
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this can be 0, 1 or 2.
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If set to 2, two copies of the volume group metadata
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are held on the PV, one at the front of the PV and one at the end.
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If set to 1 (the default), one copy is kept at the front of the PV
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(starting in the 5th sector).
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If set to 0, no copies are kept on this PV - you might wish to use this
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with VGs containing large numbers of PVs. But if you do this and
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then later use \fBvgsplit\fP you must ensure that each VG is still going
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to have a suitable number of copies of the metadata after the split!
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.TP
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.BR \-\-restorefile " file"
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In conjunction with \fB--uuid\fP, this extracts the location and size
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of the data on the PV from the file (produced by \fBvgcfgbackup\fP)
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and ensures that the metadata that the program produces is consistent
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with the contents of the file i.e. the physical extents will be in
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the same place and not get overwritten by new metadata. This provides
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a mechanism to upgrade the metadata format or to add/remove metadata
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areas. Use with care. See also \fBvgconvert\fP(8).
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.TP
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.BR \-\-labelsector " sector"
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By default the PV is labelled with an LVM2 identifier in its second
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sector (sector 1). This lets you use a different sector near the
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start of the disk (between 0 and 3 inclusive - see LABEL_SCAN_SECTORS
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in the source). Use with care.
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.TP
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.BR \-\-setphysicalvolumesize " size"
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Overrides the automatically-detected size of the PV. Use with care.
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.SH EXAMPLES
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Initialize partition #4 on the third SCSI disk and the entire fifth
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SCSI disk for later use by LVM:
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.sp
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.B pvcreate /dev/sdc4 /dev/sde
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.sp
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If the 2nd SCSI disk is a 4KB sector drive that compensates for windows
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partitioning (sector 7 is the lowest aligned logical block, the 4KB
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sectors start at LBA -1, and consequently sector 63 is aligned on a 4KB
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boundary) manually account for this when initializing for use by LVM:
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.sp
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.B pvcreate --dataalignmentoffset 7s /dev/sdb
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.sp
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.SH SEE ALSO
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.BR lvm.conf (5),
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.BR lvm (8),
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.BR vgcreate (8),
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.BR vgextend (8),
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.BR lvcreate (8),
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.BR cfdisk (8),
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.BR fdisk (8),
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.BR losetup (8),
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.BR mdadm (8),
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.BR vgcfgrestore (8),
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.BR vgconvert (8)
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