1LVCREATE(8) System Manager's Manual LVCREATE(8)
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6 lvcreate - create a logical volume in an existing volume group
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9 lvcreate [--addtag Tag] [--alloc AllocationPolicy] [-A/--autobackup
10 y/n] [-C/--contiguous y/n] [-d/--debug] [-h/-?/--help] [-i/--stripes
11 Stripes [-I/--stripesize StripeSize]] {-l/--extents LogicalExtentsNum‐
12 ber[%{VG|FREE}] |
13 -L/--size LogicalVolumeSize[kKmMgGtT]} [-M/--persistent y/n] [--minor
14 minor] [-m/--mirrors Mirrors [--nosync] [--corelog] [-R/--regionsize
15 MirrorLogRegionSize]] [-n/--name LogicalVolumeName] [-p/--permission
16 r/rw] [-r/--readahead ReadAheadSectors] [-t/--test] [-v/--verbose]
17 [-Z/--zero y/n] VolumeGroupName [PhysicalVolumePath...]
18 lvcreate {-l/--extents LogicalExtentsNumber[%{VG|FREE}] |
20 -L/--size LogicalVolumeSize[kKmMgGtT]} [-c/--chunksize ChunkSize]
21 -s/--snapshot -n/--name SnapshotLogicalVolumeName OriginalLogicalVol‐
22 umePath
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25 lvcreate creates a new logical volume in a volume group ( see vgcre‐
26 ate(8), vgchange(8) ) by allocating logical extents from the free phys‐
27 ical extent pool of that volume group. If there are not enough free
28 physical extents then the volume group can be extended ( see vgex‐
29 tend(8) ) with other physical volumes or by reducing existing logical
30 volumes of this volume group in size ( see lvreduce(8) ).
31 The second form supports the creation of snapshot logical volumes which
32 keep the contents of the original logical volume for backup purposes.
33
35 See lvm for common options.
36 -c, --chunksize ChunkSize
38 Power of 2 chunk size for the snapshot logical volume between 4k
39 and 512k.
40 -C, --contiguous y/n
42 Sets or resets the contiguous allocation policy for logical vol‐
43 umes. Default is no contiguous allocation based on a next free
44 principle.
45 -i, --stripes Stripes
47 Gives the number of stripes. This is equal to the number of
48 physical volumes to scatter the logical volume.
49 -I, --stripesize StripeSize
51 Gives the number of kilobytes for the granularity of the
52 stripes.
53 StripeSize must be 2^n (n = 2 to 9) for metadata in LVM1 format.
54 For metadata in LVM2 format, the stripe size may be a larger
55 power of 2 but must not exceed the physical extent size.
56 -l, --extents LogicalExtentsNumber[%{VG|FREE}]
58 Gives the number of logical extents to allocate for the new log‐
59 ical volume. This can also be expressed as a percentage of the
60 total space in the Volume Group with the suffix %VG or of the
61 remaining free space with the suffix %FREE.
62 -L, --size LogicalVolumeSize[kKmMgGtTpPeE]
64 Gives the size to allocate for the new logical volume. A size
65 suffix of K for kilobytes, M for megabytes, G for gigabytes, T
66 for terabytes, P for petabytes or E for exabytes is optional.
67 Default unit is megabytes.
68 --minor minor
70 Set the minor number.
71 -M, --persistent y/n
73 Set to y to make the minor number specified persistent.
74 -m, --mirrors Mirrors
76 Creates a mirrored logical volume with "Mirrors" copies. For
77 example, specifying "-m 1" would result in a mirror with two-
78 sides; that is, a linear volume plus one copy.
79 Specifying the optional argument "--nosync" will cause the cre‐
81 ation of the mirror to skip the initial resynchronization. Any
82 data written afterwards will be mirrored, but the original con‐
83 tents will not be copied. This is useful for skipping a poten‐
84 tially long and resource intensive initial sync.
85 Specifying the optional argument "--corelog" will create a mir‐
87 ror with an in-memory log verses a disk-based (persistent) log.
88 While this removes the need for an extra log device and *may* be
89 slightly faster, it requires that the entire mirror be resyn‐
90 chronized upon each instantiation (e.g. a reboot).
91 -n, --name LogicalVolumeName
93 The name for the new logical volume.
94 Without this option a default names of "lvol#" will be generated
95 where # is the LVM internal number of the logical volume.
96 -p, --permission r/w
98 Set access permissions to read only or read and write.
99 Default is read and write.
100 -r, --readahead ReadAheadSectors
102 Set read ahead sector count of this logical volume to a value
103 between 2 and 120. Ignored by device-mapper.
104 -R, --regionsize MirrorLogRegionSize
106 A mirror is divided into regions of this size (in MB), and the
107 mirror log uses this granularity to track which regions are in
108 sync.
109 -s, --snapshot
111 Create a snapshot logical volume (or snapshot) for an existing,
112 so called original logical volume (or origin). Snapshots pro‐
113 vide a 'frozen image' of the contents of the origin while the
114 origin can still be updated. They enable consistent backups and
115 online recovery of removed/overwritten data/files. The snapshot
116 does not need the same amount of storage the origin has. In a
117 typical scenario, 15-20% might be enough. In case the snapshot
118 runs out of storage, use lvextend(8) to grow it. Shrinking a
119 snapshot is supported by lvreduce(8) as well. Run lvdisplay(8)
120 on the snapshot in order to check how much data is allocated to
121 it.
122 -Z, --zero y/n
124 Controls zeroing of the first KB of data in the new logical vol‐
125 ume.
126 Default is yes.
127 Volume will not be zeroed if read only flag is set.
128 Snapshot volumes are zeroed always.
129 Warning: trying to mount an unzeroed logical volume can cause
131 the system to hang.
132
134 "lvcreate -i 3 -I 8 -L 100M vg00" tries to create a striped logical
135 volume with 3 stripes, a stripesize of 8KB and a size of 100MB in the
136 volume group named vg00. The logical volume name will be chosen by
137 lvcreate.
138 "lvcreate -m1 -L 500M vg00" tries to create a mirror logical volume
140 with 2 sides with a useable size of 500 MiB. This operation would
141 require 3 devices - two for the mirror devices and one for the disk
142 log.
143 "lvcreate --size 100m --snapshot --name snap /dev/vg00/lvol1"
145 creates a snapshot logical volume named /dev/vg00/snap which has access
146 to the contents of the original logical volume named /dev/vg00/lvol1 at
147 snapshot logical volume creation time. If the original logical volume
148 contains a file system, you can mount the snapshot logical volume on an
149 arbitrary directory in order to access the contents of the filesystem
150 to run a backup while the original filesystem continues to get updated.
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154 lvm(8), vgcreate(8), lvremove(8), lvrename(8) lvextend(8), lvreduce(8),
155 lvdisplay(8), lvscan(8)
156Sistina Software UK LVM TOOLS LVCREATE(8)