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96 lines
3.2 KiB
Groff
96 lines
3.2 KiB
Groff
.TH VGCREATE 8 "LVM TOOLS" "Sistina Software UK" \" -*- nroff -*-
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.SH NAME
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vgcreate \- create a volume group
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.SH SYNOPSIS
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.B vgcreate
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.RB [ \-\-addtag
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.IR Tag ]
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.RB [ \-\-alloc
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.IR AllocationPolicy ]
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.RB [ \-A | \-\-autobackup " {" y | n }]
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.RB [ \-d | \-\-debug ]
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.RB [ \-h | \-\-help ]
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.RB [ \-l | \-\-maxlogicalvolumes
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.IR MaxLogicalVolumes ]
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.RB [ -M | \-\-metadatatype type]
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.RB [ -p | \-\-maxphysicalvolumes
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.IR MaxPhysicalVolumes ]
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.RB [ \-s | \-\-physicalextentsize
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.IR PhysicalExtentSize [ \fBkKmMgGtT\fR ]]
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.RB [ \-t | \-\-test ]
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.RB [ \-v | \-\-verbose ]
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.RB [ \-\-version ]
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.I VolumeGroupName PhysicalVolumePath
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.RI [ PhysicalVolumePath ...]
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.SH DESCRIPTION
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.B vgcreate
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creates a new volume group called
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.I VolumeGroupName
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using the block special device
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.IR PhysicalVolumePath
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previously configured for LVM with
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.BR pvcreate (8).
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.SH OPTIONS
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See \fBlvm\fP for common options.
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.TP
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.BR \-l ", " \-\-maxlogicalvolumes " " \fIMaxLogicalVolumes\fR
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Sets the maximum number of logical volumes allowed in this
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volume group.
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The setting can be changed with \fBvgchange\fP.
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For volume groups with metadata in lvm1 format, the limit
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and default value is 255.
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If the metadata uses lvm2 format, the default value is 0
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which removes this restriction: there is then no limit.
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.TP
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.BR \-p ", " \-\-maxphysicalvolumes " " \fIMaxPhysicalVolumes\fR
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Sets the maximum number of physical volumes that can belong
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to this volume group.
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The setting can be changed with \fBvgchange\fP.
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For volume groups with metadata in lvm1 format, the limit
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and default value is 255.
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If the metadata uses lvm2 format, the default value is 0
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which removes this restriction: there is then no limit.
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If you have a large number of physical volumes in
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a volume group with metadata in lvm2 format,
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for tool performance reasons, you should consider
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some use of \fB--metadatacopies 0\fP
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as described in \fBpvcreate(8)\fP.
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.TP
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.BR \-s ", " \-\-physicalextentsize " " \fIPhysicalExtentSize\fR[\fBkKmMgGtT\fR]
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Sets the physical extent size on physical volumes of this volume group.
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A size suffix (k for kilobytes up to t for terabytes) is optional, megabytes
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is the default if no suffix is present. Values can be from 8 KB to 16 GB in
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powers of 2. The default is 4 MB.
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Once this value has been set, it is difficult to change it without recreating
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the volume group which would involve backing up and restoring data on any
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logical volumes.
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If the volume group metadata uses lvm1 format, there is a limit of 65534
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extents in each logical volume, so the default of 4 MB leads to a maximum
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logical volume size of around 256GB.
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If the volume group metadata uses lvm2 format there is no such restriction,
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although having a large number of extents will slow down
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the tools but have no impact on I/O performance to the logical volume.
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The 2.4 kernel has a limitation of 2TB per block device.
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.SH EXAMPLES
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To create a volume group named
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.B test_vg
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using physical volumes
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.BR /dev/hdk1 ", and " /dev/hdl1
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with default physical extent size of 4MB:
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.nf
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\ vgcreate test_vg /dev/sdk1 /dev/sdl1
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.fi
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.SH SEE ALSO
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.BR lvm (8),
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.BR pvdisplay (8),
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.BR pvcreate (8),
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.BR vgdisplay (8),
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.BR vgextend (8),
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.BR vgreduce (8),
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.BR lvcreate (8),
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.BR lvdisplay (8),
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.BR lvextend (8),
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.BR lvreduce (8)
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