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] [--noudevsync]
11 [--ignoremonitoring] [--monitor {y|n}] [-i|--stripes Stripes
12 [-I|--stripesize StripeSize]] {-l|--extents LogicalExtentsNum‐
13 ber[%{VG|PVS|FREE}] |
14 -L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]} [-M|--persistent y|n]
15 [--minor minor] [-m|--mirrors Mirrors [--nosync] [--mirrorlog
16 {disk|core|mirrored}] [--corelog] [-R|--regionsize MirrorLogRegion‐
17 Size]] [-n|--name LogicalVolumeName] [-p|--permission r|rw]
18 [-r|--readahead ReadAheadSectors|auto|none] [-t|--test] [--type Seg‐
19 mentType] [-v|--verbose] [-Z|--zero y|n] VolumeGroupName [PhysicalVol‐
20 umePath[:PE[-PE]]...]
21 lvcreate {-l|--extents LogicalExtentsNumber[%{VG|FREE|ORIGIN}] |
23 -L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]} [-c|--chunksize Chunk‐
24 Size] [--noudevsync] [--ignoremonitoring] [--monitor {y|n}] -n|--name
25 SnapshotLogicalVolumeName {{-s|--snapshot} OriginalLogicalVolumePath |
26 [-s|--snapshot] VolumeGroupName --virtualsize VirtualSize}
27
29 lvcreate creates a new logical volume in a volume group ( see vgcre‐
30 ate(8), vgchange(8) ) by allocating logical extents from the free phys‐
31 ical extent pool of that volume group. If there are not enough free
32 physical extents then the volume group can be extended ( see vgex‐
33 tend(8) ) with other physical volumes or by reducing existing logical
34 volumes of this volume group in size ( see lvreduce(8) ). If you spec‐
35 ify one or more PhysicalVolumes, allocation of physical extents will be
36 restricted to these volumes.
37 The second form supports the creation of snapshot logical volumes which
38 keep the contents of the original logical volume for backup purposes.
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41 See lvm for common options.
42 -c, --chunksize ChunkSize
44 Power of 2 chunk size for the snapshot logical volume between 4k
45 and 512k.
46 -C, --contiguous y|n
48 Sets or resets the contiguous allocation policy for logical vol‐
49 umes. Default is no contiguous allocation based on a next free
50 principle.
51 -i, --stripes Stripes
53 Gives the number of stripes. This is equal to the number of
54 physical volumes to scatter the logical volume.
55 -I, --stripesize StripeSize
57 Gives the number of kilobytes for the granularity of the
58 stripes.
59 StripeSize must be 2^n (n = 2 to 9) for metadata in LVM1 format.
60 For metadata in LVM2 format, the stripe size may be a larger
61 power of 2 but must not exceed the physical extent size.
62 -l, --extents LogicalExtentsNumber[%{VG|PVS|FREE|ORIGIN}]
64 Gives the number of logical extents to allocate for the new log‐
65 ical volume. The number can also be expressed as a percentage
66 of the total space in the Volume Group with the suffix %VG, as a
67 percentage of the remaining free space in the Volume Group with
68 the suffix %FREE, as a percentage of the remaining free space
69 for the specified PhysicalVolume(s) with the suffix %PVS, or
70 (for a snapshot) as a percentage of the total space in the Ori‐
71 gin Logical Volume with the suffix %ORIGIN.
72 -L, --size LogicalVolumeSize[bBsSkKmMgGtTpPeE]
74 Gives the size to allocate for the new logical volume. A size
75 suffix of K for kilobytes, M for megabytes, G for gigabytes, T
76 for terabytes, P for petabytes or E for exabytes is optional.
77 Default unit is megabytes.
78 --minor minor
80 Set the minor number.
81 -M, --persistent y|n
83 Set to y to make the minor number specified persistent.
84 -m, --mirrors Mirrors
86 Creates a mirrored logical volume with Mirrors copies. For
87 example, specifying "-m 1" would result in a mirror with two-
88 sides; that is, a linear volume plus one copy.
89 Specifying the optional argument --nosync will cause the cre‐
91 ation of the mirror to skip the initial resynchronization. Any
92 data written afterwards will be mirrored, but the original con‐
93 tents will not be copied. This is useful for skipping a poten‐
94 tially long and resource intensive initial sync of an empty
95 device.
96 The optional argument --mirrorlog specifies the type of log to
98 be used. The default is disk, which is persistent and requires
99 a small amount of storage space, usually on a separate device
100 from the data being mirrored. Using core means the mirror is
101 regenerated by copying the data from the first device again each
102 time the device is activated, for example, after every reboot.
103 Using "mirrored" will create a persistent log that is itself
104 mirrored.
105 The optional argument --corelog is equivalent to --mirrorlog
107 core.
108 -n, --name LogicalVolumeName
111 The name for the new logical volume.
112 Without this option a default names of "lvol#" will be generated
113 where # is the LVM internal number of the logical volume.
114 --noudevsync
116 Disable udev synchronisation. The process will not wait for
117 notification from udev. It will continue irrespective of any
118 possible udev processing in the background. You should only use
119 this if udev is not running or has rules that ignore the devices
120 LVM2 creates.
121 --monitor y|n
123 Start or avoid monitoring a mirrored or snapshot logical volume
124 with dmeventd, if it is installed. If a device used by a moni‐
125 tored mirror reports an I/O error, the failure is handled
126 according to mirror_image_fault_policy and mirror_log_fault_pol‐
127 icy set in lvm.conf.
128 --ignoremonitoring
130 Make no attempt to interact with dmeventd unless --monitor is
131 specified.
132 -p, --permission r|rw
134 Set access permissions to read only or read and write.
135 Default is read and write.
136 -r, --readahead ReadAheadSectors|auto|none
138 Set read ahead sector count of this logical volume. For volume
139 groups with metadata in lvm1 format, this must be a value
140 between 2 and 120. The default value is "auto" which allows the
141 kernel to choose a suitable value automatically. "None" is
142 equivalent to specifying zero.
143 -R, --regionsize MirrorLogRegionSize
145 A mirror is divided into regions of this size (in MB), and the
146 mirror log uses this granularity to track which regions are in
147 sync.
148 -s, --snapshot
150 Create a snapshot logical volume (or snapshot) for an existing,
151 so called original logical volume (or origin). Snapshots pro‐
152 vide a 'frozen image' of the contents of the origin while the
153 origin can still be updated. They enable consistent backups and
154 online recovery of removed/overwritten data/files. The snapshot
155 does not need the same amount of storage the origin has. In a
156 typical scenario, 15-20% might be enough. In case the snapshot
157 runs out of storage, use lvextend(8) to grow it. Shrinking a
158 snapshot is supported by lvreduce(8) as well. Run lvdisplay(8)
159 on the snapshot in order to check how much data is allocated to
160 it. Note that a small amount of the space you allocate to the
161 snapshot is used to track the locations of the chunks of data,
162 so you should allocate slightly more space than you actually
163 need and monitor the rate at which the snapshot data is growing
164 so you can avoid running out of space.
165 --type SegmentType
167 Create a logical volume that uses the specified segment type
168 (e.g. "mirror", "snapshot", "striped"). Especially useful when
169 no existing commandline switch alias enables the use of the
170 desired type (e.g. "error" or "zero" types). Many segment types
171 already have a commandline switch alias that will enable their
172 use (-s is an alias for --type snapshot).
173 --virtualsize VirtualSize
175 Create a sparse device of the given size (in MB by default)
176 using a snapshot. Anything written to the device will be
177 returned when reading from it. Reading from other areas of the
178 device will return blocks of zeros. It is implemented by creat‐
179 ing a hidden virtual device of the requested size using the zero
180 target. A suffix of _vorigin is used for this device.
181 -Z, --zero y|n
183 Controls zeroing of the first KB of data in the new logical vol‐
184 ume.
185 Default is yes.
186 Volume will not be zeroed if read only flag is set.
187 Snapshot volumes are zeroed always.
188 Warning: trying to mount an unzeroed logical volume can cause
190 the system to hang.
191
193 "lvcreate -i 3 -I 8 -L 100M vg00" tries to create a striped logical
194 volume with 3 stripes, a stripesize of 8KB and a size of 100MB in the
195 volume group named vg00. The logical volume name will be chosen by
196 lvcreate.
197 "lvcreate -m1 -L 500M vg00" tries to create a mirror logical volume
199 with 2 sides with a useable size of 500 MiB. This operation would
200 require 3 devices - two for the mirror devices and one for the disk
201 log.
202 "lvcreate -m1 --mirrorlog core -L 500M vg00" tries to create a mirror
204 logical volume with 2 sides with a useable size of 500 MiB. This oper‐
205 ation would require 2 devices - the log is "in-memory".
206 "lvcreate --size 100m --snapshot --name snap /dev/vg00/lvol1"
208 creates a snapshot logical volume named /dev/vg00/snap which has access
209 to the contents of the original logical volume named /dev/vg00/lvol1 at
210 snapshot logical volume creation time. If the original logical volume
211 contains a file system, you can mount the snapshot logical volume on an
212 arbitrary directory in order to access the contents of the filesystem
213 to run a backup while the original filesystem continues to get updated.
214 "lvcreate --virtualsize 1T --size 100M --snapshot --name sparse vg1"
216 creates a sparse device named /dev/vg1/sparse of size 1TB with space
217 for just under 100MB of actual data on it.
218 "lvcreate -L 64M -n lvol1 vg00 /dev/sda:0-7 /dev/sdb:0-7"
220 creates a linear logical volume "vg00/lvol1" using physical extents
221 /dev/sda:0-7 and /dev/sdb:0-7 for allocation of extents.
222
226 lvm(8), vgcreate(8), lvremove(8), lvrename(8) lvextend(8), lvreduce(8),
227 lvdisplay(8), lvscan(8)
228Sistina Software UK LVM TOOLS 2.02.84(2) (2011-02-09) LVCREATE(8)