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lvcreate(8) [centos man page]

LVCREATE(8)						      System Manager's Manual						       LVCREATE(8)

NAME
lvcreate - create a logical volume in an existing volume group SYNOPSIS
lvcreate [--addtag Tag] [--alloc AllocationPolicy] [-a|--activate [a|e|l]{y|n}] [-k|--setactivationskip {y|n}] [-K|--ignoreactivationskip] [-A|--autobackup {y|n}] [-C|--contiguous {y|n}] [-d|--debug] [-h|-?|--help] [--noudevsync] [--ignoremonitoring] [--monitor {y|n}] [--[raid]maxrecoveryrate Rate] [--[raid]minrecoveryrate Rate] [-i|--stripes Stripes [-I|--stripesize StripeSize]] {[-l|--extents LogicalEx- tentsNumber[%{VG|PVS|FREE}] | -L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]] | -V|--virtualsize VirtualSize[bBsSkKmMgGtTpPeE]} [-M|--per- sistent {y|n}] [--minor minor] [-m|--mirrors Mirrors [--nosync] [--mirrorlog {disk|core|mirrored} | --corelog] [-R|--regionsize Mirror- LogRegionSize]] [-n|--name LogicalVolume{Name|Path}] [-p|--permission {r|rw}] [-r|--readahead {ReadAheadSectors|auto|none}] [-t|--test] [-T|--thin [--cachemode {writeback|writethrough} [-c|--chunksize ChunkSize[bBsSkKmMgG]] [--discards {ignore|nopassdown|passdown}] [--pool- metadatasize MetadataVolumeSize[bBsSkKmMgG]] [--poolmetadataspare {y|n}]] [--thinpool ThinPoolLogicalVolume{Name|Path} [-s|--snapshot [Vol- umeGroup{Name|Path}/] ExternalOriginLogicalVolumeName]] [--type SegmentType] [-v|--verbose] [-W|--wipesignatures] [-Z|--zero {y|n}] Vol- umeGroup{Name|Path}[/ThinPoolLogicalVolumeName] [PhysicalVolumePath[:PE[-PE]]...] lvcreate [-l|--extents LogicalExtentsNumber[%{VG|FREE|ORIGIN}] | -L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]] [-c|--chunksize Chunk- Size[bBsSkK]] [--noudevsync] [--ignoremonitoring] [--monitor {y|n}] [-n|--name SnapshotLogicalVolume{Name|Path}] -s|--snapshot {[Vol- umeGroup{Name|Path}/]OriginalLogicalVolumeName -V|--virtualsize VirtualSize[bBsSkKmMgGtTpPeE]} DESCRIPTION
lvcreate creates a new logical volume in a volume group (see vgcreate(8), vgchange(8)) by allocating logical extents from the free physical extent pool of that volume group. If there are not enough free physical extents then the volume group can be extended (see vgextend(8)) with other physical volumes or by reducing existing logical volumes of this volume group in size (see lvreduce(8)). If you specify one or more PhysicalVolumes, allocation of physical extents will be restricted to these volumes. The second form supports the creation of snapshot logical volumes which keep the contents of the original logical volume for backup pur- poses. OPTIONS
See lvm(8) for common options. -a, --activate {y|ay|n|ey|en|ly|ln} Controls the availability of the Logical Volumes for immediate use after the command finishes running. By default, new Logical Vol- umes are activated (-ay). If it is possible technically, -an will leave the new Logical Volume inactive. But for example, snapshots can only be created in the active state so -an cannot be used with --snapshot. Normally the --zero n argument has to be supplied too because zeroing (the default behaviour) also requires activation. If autoactivation option is used (-aay), the logical volume is activated only if it matches an item in the activation/auto_activation_volume_list set in lvm.conf(5). For autoactivated logical volumes, --zero n and --wipesignatures n is always assumed and it can't be overridden. If the clustered locking is enabled, -aey will activate exclusively on one node and -a{a|l}y will activate only on the local node. -k, --setactivationskip {y|n} Controls whether Logical Volumes are persistently flagged to be skipped during activation. By default, thin snapshot volumes are flagged for activation skip. To activate such volumes, an extra -K/--ignoreactivationskip option must be used. The flag is not applied during deactivation. Use lvchange -k/--setactivationskip {y | n} command to attach or detach the flag for existing volumes. To see whether the flag is attached, use lvs command where the state of the flag is reported within lv_attr bits. -K, --ignoreactivationskip Ignore the flag to skip Logical Volumes during activation. --cachemode {writeback|writethrough} Specifying a cache mode determines when the writes to a cache LV are considered complete. When writeback is specified, a write is considered complete as soon as it is stored in the cache pool LV. If writethough is specified, a write is considered complete only when it has been stored in the cache pool LV and on the origin LV. While writethrough may be slower for writes, it is more resilient if something should happen to a device associated with the cache pool LV. -c, --chunksize ChunkSize[bBsSkKmMgG] Gives the size of chunk for snapshot, cache pool and thin pool logical volumes. Default unit is in kilobytes. For snapshots the value must be power of 2 between 4KiB and 512KiB and the default value is 4. For cache pool LVs the value must be between 32KiB and 1GiB. The default is 64KiB. Values must be a multiple of 32KiB. For thin pools the value must be between 64KiB and 1GiB and the default value starts with 64 and scales up to fit the pool metadata size within 128MiB, if the pool metadata size is not specified. Thin pool target version <1.4 requires the value to be a power of 2. The newer target version relaxes limitation to be a multiple of 64KiB. For target version <1.5 discard is not supported for non power of 2 values. -C, --contiguous {y|n} Sets or resets the contiguous allocation policy for logical volumes. Default is no contiguous allocation based on a next free prin- ciple. --discards {ignore|nopassdown|passdown} Sets discards behavior for thin pool. Default is passdown. -i, --stripes Stripes Gives the number of stripes. This is equal to the number of physical volumes to scatter the logical volume. When creating a RAID 4/5/6 logical volume, the extra devices which are necessary for parity are internally accounted for. Specifying -i3 would use 3 devices for striped logical volumes, 4 devices for RAID 4/5, and 5 devices for RAID 6. Alternatively, RAID 4/5/6 will stripe across all PVs in the volume group or all of the PVs specified if the -i argument is omitted. -I, --stripesize StripeSize Gives the number of kilobytes for the granularity of the stripes. StripeSize must be 2^n (n = 2 to 9) for metadata in LVM1 format. For metadata in LVM2 format, the stripe size may be a larger power of 2 but must not exceed the physical extent size. --ignoremonitoring Make no attempt to interact with dmeventd unless --monitor is specified. -l, --extents LogicalExtentsNumber[%{VG|PVS|FREE|ORIGIN}] Gives the number of logical extents to allocate for the new logical volume. The total number of physical extents allocated will be greater than this, for example, if the volume is mirrored. The number can also be expressed as a percentage of the total space in the Volume Group with the suffix %VG, as a percentage of the remaining free space in the Volume Group with the suffix %FREE, as a percentage of the remaining free space for the specified PhysicalVolume(s) with the suffix %PVS, or (for a snapshot) as a percentage of the total space in the Origin Logical Volume with the suffix %ORIGIN. When expressed as a percentage, the number is treated as an approximate upper limit for the total number of physical extents to be allocated (including extents used by any mirrors, for example). -L, --size LogicalVolumeSize[bBsSkKmMgGtTpPeE] Gives the size to allocate for the new logical volume. A size suffix of B for bytes, S for sectors as 512 bytes, K for kilobytes, M for megabytes, G for gigabytes, T for terabytes, P for petabytes or E for exabytes is optional. Default unit is megabytes. -m, --mirrors Mirrors Creates a mirrored logical volume with Mirrors copies. For example, specifying -m1 would result in a mirror with two-sides; that is, a linear volume plus one copy. Specifying the optional argument --nosync will cause the creation of the mirror to skip the initial resynchronization. Any data written afterwards will be mirrored, but the original contents will not be copied. This is useful for skipping a potentially long and resource intensive initial sync of an empty device. There are two implementations of mirroring which can be used and correspond to the "raid1" and "mirror" segment types. The default is "raid1". See the --type option for more information if you would like to use the legacy "mirror" segment type. The --mirrorlog and --corelog options apply to the "mirror" segment type only. The optional argument --mirrorlog specifies the type of log to be used for logical volumes utilizing the legacy "mirror" segment type. The default is disk, which is persistent and requires a small amount of storage space, usually on a separate device from the data being mirrored. Using core means the mirror is regenerated by copying the data from the first device each time the logical volume is activated, like after every reboot. Using mirrored will create a persistent log that is itself mirrored. When the legacy "mirror" segment type is used, the optional argument --corelog is equivalent to --mirrorlog core. -M, --persistent {y|n} Set to y to make the minor number specified persistent. --minor minor Sets the minor number. --monitor {y|n} Starts or avoids monitoring a mirrored, snapshot or thin pool logical volume with dmeventd, if it is installed. If a device used by a monitored mirror reports an I/O error, the failure is handled according to activation/mirror_image_fault_policy and activa- tion/mirror_log_fault_policy set in lvm.conf(5). -n, --name LogicalVolume{Name|Path} Sets the name for the new logical volume. Without this option a default name of "lvol#" will be generated where # is the LVM internal number of the logical volume. --[raid]maxrecoveryrate Rate[bBsSkKmMgG] Sets the maximum recovery rate for a RAID logical volume. Rate is specified as an amount per second for each device in the array. If no suffix is given, then kiB/sec/device is assumed. Setting the recovery rate to 0 means it will be unbounded. --[raid]minrecoveryrate Rate[bBsSkKmMgG] Sets the minimum recovery rate for a RAID logical volume. Rate is specified as an amount per second for each device in the array. If no suffix is given, then kiB/sec/device is assumed. Setting the recovery rate to 0 means it will be unbounded. --noudevsync Disables udev synchronisation. The process will not wait for notification from udev. It will continue irrespective of any possible udev processing in the background. You should only use this if udev is not running or has rules that ignore the devices LVM2 cre- ates. -p, --permission {r|rw} Sets access permissions to read only (r) or read and write (rw). Default is read and write. --poolmetadatasize MetadataVolumeSize[bBsSkKmMgG] Sets the size of thin pool's metadata logical volume. Supported values are in range between 2MiB and 16GiB. Default value is (Pool_LV_size / Pool_LV_chunk_size * 64b). Default unit is megabytes. --poolmetadataspare {y|n} Controls creation and maintanence of pool metadata spare logical volume that will be used for automated thin pool recovery. Only one such volume is maintained within a volume group with the size of the biggest thin metadata volume. Default is yes. -r, --readahead {ReadAheadSectors|auto|none} Sets read ahead sector count of this logical volume. For volume groups with metadata in lvm1 format, this must be a value between 2 and 120. The default value is auto which allows the kernel to choose a suitable value automatically. None is equivalent to speci- fying zero. -R, --regionsize MirrorLogRegionSize A mirror is divided into regions of this size (in MiB), and the mirror log uses this granularity to track which regions are in sync. -s, --snapshot OriginalLogicalVolume{Name|Path} Creates a snapshot logical volume (or snapshot) for an existing, so called original logical volume (or origin). Snapshots provide a 'frozen image' of the contents of the origin while the origin can still be updated. They enable consistent backups and online recov- ery of removed/overwritten data/files. Thin snapshot is created when the origin is a thin volume and the size IS NOT specified. Thin snapshot shares same blocks within the thin pool volume. The non thin volume snapshot with the specified size does not need the same amount of storage the origin has. In a typical scenario, 15-20% might be enough. In case the snapshot runs out of storage, use lvextend(8) to grow it. Shrinking a snapshot is supported by lvreduce(8) as well. Run lvs(8) on the snapshot in order to check how much data is allocated to it. Note: a small amount of the space you allocate to the snapshot is used to track the locations of the chunks of data, so you should allocate slightly more space than you actually need and monitor (--monitor) the rate at which the snapshot data is growing so you can avoid running out of space. If --thinpool is specified, thin volume is created that will use given original logical volume as an external origin that serves unprovisioned blocks. Only read-only volumes can be used as exter- nal origins. To make the volume external origin, lvm expects the volume to be inactive. External origin volume can be used/shared for many thin volumes even from different thin pools. See lvconvert(8) for online conversion to thin volumes with external origin. -T, --thin, --thinpool ThinPoolLogicalVolume{Name|Path} Creates thin pool or thin logical volume or both. Specifying the optional argument --size will cause the creation of the thin pool logical volume. Specifying the optional argument --virtualsize will cause the creation of the thin logical volume from given thin pool volume. Specifying both arguments will cause the creation of both thin pool and thin volume using this pool. Requires device mapper kernel driver for thin provisioning from kernel 3.2 or newer. --type SegmentType Create a logical volume that uses the specified segment type (e.g. mirror(-m), raid5, snapshot(-s), thin(-T), thin-pool, ...). Many segment types have a commandline switch alias that will enable their use (-s is an alias for --type snapshot). However, this argument must be used when no existing commandline switch alias is available for the desired type, as is the case with cache, error, raid1, raid4, raid5, raid6, raid10 or zero. Note that the cache segment type requires a dm-cache kernel module version 1.3.0 or greater. -V, --virtualsize VirtualSize[bBsSkKmMgGtTpPeE] Creates a sparse device of the given size (in MiB by default) using a snapshot or thinly provisioned device when thin pool is speci- fied. Anything written to the device will be returned when reading from it. Reading from other areas of the device will return blocks of zeros. Virtual snapshot is implemented by creating a hidden virtual device of the requested size using the zero target. A suffix of _vorigin is used for this device. Note: using sparse snapshots is not efficient for larger device sizes (GiB), thin pro- visioning should be used for this case. -W, --wipesignatures {y|n} Controls wiping of detected signatures on newly created Logical Volume. If this option is not specified, then by default signature wiping is done each time the zeroing (-Z/--zero) is done. This default behaviour can be controlled by allocation/wipe_signa- tures_when_zeroing_new_lvs setting found in lvm.conf(5). If blkid wiping is used (allocation/use_blkid_wiping setting in lvm.conf(5)) and LVM2 is compiled with blkid wiping support, then blkid(8) library is used to detect the signatures (use blkid -k command to list the signatures that are recognized). Otherwise, native LVM2 code is used to detect signatures (MD RAID, swap and LUKS signatures are detected only in this case). Logical Volume is not wiped if the read only flag is set. -Z, --zero {y|n} Controls zeroing of the first 4KiB of data in the new logical volume. Default is yes. Volume will not be zeroed if the read only flag is set. Snapshot volumes are zeroed always. Warning: trying to mount an unzeroed logical volume can cause the system to hang. Examples Creates a striped logical volume with 3 stripes, a stripe size of 8KiB and a size of 100MiB in the volume group named vg00. The logical volume name will be chosen by lvcreate: lvcreate -i 3 -I 8 -L 100M vg00 Creates a mirror logical volume with 2 sides with a useable size of 500 MiB. This operation would require 3 devices (or option --alloc anywhere ) - two for the mirror devices and one for the disk log: lvcreate -m1 -L 500M vg00 Creates a mirror logical volume with 2 sides with a useable size of 500 MiB. This operation would require 2 devices - the log is "in-mem- ory": lvcreate -m1 --mirrorlog core -L 500M vg00 Creates a snapshot logical volume named /dev/vg00/snap which has access to the contents of the original logical volume named /dev/vg00/lvol1 at snapshot logical volume creation time. If the original logical volume contains a file system, you can mount the snapshot logical volume on an arbitrary directory in order to access the contents of the filesystem to run a backup while the original filesystem continues to get updated: lvcreate --size 100m --snapshot --name snap /dev/vg00/lvol1 Creates a sparse device named /dev/vg1/sparse of size 1TiB with space for just under 100MiB of actual data on it: lvcreate --virtualsize 1T --size 100M --snapshot --name sparse vg1 Creates a linear logical volume "vg00/lvol1" using physical extents /dev/sda:0-7 and /dev/sdb:0-7 for allocation of extents: lvcreate -L 64M -n lvol1 vg00 /dev/sda:0-7 /dev/sdb:0-7 Creates a 5GiB RAID5 logical volume "vg00/my_lv", with 3 stripes (plus a parity drive for a total of 4 devices) and a stripesize of 64KiB: lvcreate --type raid5 -L 5G -i 3 -I 64 -n my_lv vg00 Creates a RAID5 logical volume "vg00/my_lv", using all of the free space in the VG and spanning all the PVs in the VG: lvcreate --type raid5 -l 100%FREE -n my_lv vg00 Creates a 5GiB RAID10 logical volume "vg00/my_lv", with 2 stripes on 2 2-way mirrors. Note that the -i and -m arguments behave differ- ently. The -i specifies the number of stripes. The -m specifies the number of additional copies: lvcreate --type raid10 -L 5G -i 2 -m 1 -n my_lv vg00 Creates 100MiB pool logical volume for thin provisioning build with 2 stripes 64KiB and chunk size 256KiB together with 1TiB thin provi- sioned logical volume "vg00/thin_lv": lvcreate -i 2 -I 64 -c 256 -L100M -T vg00/pool -V 1T --name thin_lv Creates a thin snapshot volume "thinsnap" of thin volume "thinvol" that will share the same blocks within the thin pool. Note: the size MUST NOT be specified, otherwise the non-thin snapshot is created instead: lvcreate -s vg00/thinvol --name thinsnap Creates a thin snapshot volume of read-only inactive volume "origin" which then becomes the thin external origin for the thin snapshot vol- ume in vg00 that will use an existing thin pool "vg00/pool": lvcreate -s --thinpool vg00/pool origin Create a cache pool LV that can later be used to cache one logical volume. lvcreate --type cache-pool -L 1G -n my_lv_cachepool vg /dev/fast1 If there is an existing cache pool LV, create the large slow device (i.e. the origin LV) and link it to the supplied cache pool LV, creat- ing a cache LV. lvcreate --type cache -L 100G -n my_lv vg/my_lv_cachepool /dev/slow1 If there is an existing logical volume, create the small and fast cache pool LV and link it to the supplied existing logical volume (i.e. the origin LV), creating a cache LV. lvcreate --type cache -L 1G -n my_lv_cachepool vg/my_lv /dev/fast1 SEE ALSO
lvm(8), lvm.conf(5), lvconvert(8), lvchange(8), lvextend(8), lvreduce(8), lvremove(8), lvrename(8) lvs(8), lvscan(8), vgcreate(8) Sistina Software UK LVM TOOLS 2.02.105(2)-RHEL7 (2014-03-26) LVCREATE(8)

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