The `lvcreate` command is used to create Logical Volumes (LVs) on Linux systems that utilize the Logical Volume Manager (LVM).
LVM allows you to manage storage more efficiently by creating, resizing, and removing logical volumes without the need to repartition the physical disks.
In this guide, we will explore four examples of using the `lvcreate` command to create logical volumes on Linux.
Example 1: Creating a new logical volume
To create a new logical volume, you need to specify the size, the name of the logical volume, and the volume group (VG) it will belong to. For example, to create a 10 GB logical volume named “my_logical_volume” in the volume group “my_volume_group”, run the following command:
sudo lvcreate -L 10G -n my_logical_volume my_volume_group
Example 2: Creating a logical volume using a percentage of free space
Instead of specifying an exact size, you can create a logical volume using a percentage of the available free space in the volume group. To create a logical volume named “my_logical_volume” that uses 50% of the free space in the volume group “my_volume_group”, use the following command:
sudo lvcreate -l 50%FREE -n my_logical_volume my_volume_group
Example 3: Creating a logical volume with specific extents
LVM uses a concept called “extents” to manage space within a volume group. You can create a logical volume with a specific number of extents. To create a logical volume named “my_logical_volume” with 100 extents from the volume group “my_volume_group”, run the following command:
sudo lvcreate -l 100 -n my_logical_volume my_volume_group
Example 4: Creating a mirrored logical volume
To enhance data protection, you can create a mirrored logical volume that maintains multiple copies of the data. For example, to create a 10 GB mirrored logical volume named “my_logical_volume” in the volume group “my_volume_group” with one mirror, use the following command:
sudo lvcreate -L 10G -m 1 -n my_logical_volume my_volume_group
The -m 1 flag indicates that one mirror copy of the data will be maintained.
Commands and Their Functions:
- lvcreate – A command used to create logical volumes in a volume group managed by the Logical Volume Manager (LVM).
- -L – Specifies the size of the logical volume to be created.
- -n – Defines the name of the new logical volume.
- -l – Specifies the percentage of free space or the number of extents to use for the logical volume.
- -m – Indicates the number of mirror copies to maintain for a mirrored logical volume.
Conclusion
By following the examples provided in this guide, you now have a better understanding of how to use the `lvcreate` command to create logical volumes on Linux systems. You can create logical volumes with specific sizes, using a percentage of free space, or with specific extents. Additionally, you can create mirrored logical volumes for enhanced data protection.
To see more lvcreate command options, initiate the following command:
[root@centos7 ~]# lvcreate --help
lvcreate: Create a logical volume
lvcreate
[-A|--autobackup {y|n}]
[-a|--activate [a|e|l]{y|n}]
[--addtag Tag]
[--alloc AllocationPolicy]
[--cachemode CacheMode]
[-C|--contiguous {y|n}]
[-d|--debug]
[-h|-?|--help]
[--ignoremonitoring]
[--monitor {y|n}]
[-i|--stripes Stripes [-I|--stripesize StripeSize]]
[-k|--setactivationskip {y|n}]
[-K|--ignoreactivationskip]
{-l|--extents LogicalExtentsNumber[%{VG|PVS|FREE}] |
-L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]}
[-M|--persistent {y|n}] [--major major] [--minor minor]
[-m|--mirrors Mirrors [--nosync] [{--mirrorlog {disk|core|mirrored}|--corelog}]]
[-n|--name LogicalVolumeName]
[--noudevsync]
[-p|--permission {r|rw}]
[--[raid]minrecoveryrate Rate]
[--[raid]maxrecoveryrate Rate]
[-r|--readahead ReadAheadSectors|auto|none]
[-R|--regionsize MirrorLogRegionSize]
[-T|--thin [-c|--chunksize ChunkSize]
[--discards {ignore|nopassdown|passdown}]
[--poolmetadatasize MetadataSize[bBsSkKmMgG]]]
[--poolmetadataspare {y|n}]
[--thinpool ThinPoolLogicalVolume{Name|Path}]
[-t|--test]
[--type VolumeType]
[-v|--verbose]
[-W|--wipesignatures {y|n}]
[-Z|--zero {y|n}]
[--version]
VolumeGroupName [PhysicalVolumePath...]
lvcreate
{ {-s|--snapshot} OriginalLogicalVolume[Path] |
[-s|--snapshot] VolumeGroupName[Path] -V|--virtualsize VirtualSize}
{-T|--thin} VolumeGroupName[Path][/PoolLogicalVolume]
-V|--virtualsize VirtualSize}
[-c|--chunksize]
[-A|--autobackup {y|n}]
[--addtag Tag]
[--alloc AllocationPolicy]
[-C|--contiguous {y|n}]
[-d|--debug]
[--discards {ignore|nopassdown|passdown}]
[-h|-?|--help]
[--ignoremonitoring]
[--monitor {y|n}]
[-i|--stripes Stripes [-I|--stripesize StripeSize]]
[-k|--setactivationskip {y|n}]
[-K|--ignoreactivationskip]
{-l|--extents LogicalExtentsNumber[%{VG|FREE|ORIGIN}] |
-L|--size LogicalVolumeSize[bBsSkKmMgGtTpPeE]}
[--poolmetadatasize MetadataVolumeSize[bBsSkKmMgG]]
[-M|--persistent {y|n}] [--major major] [--minor minor]
[-n|--name LogicalVolumeName]
[--noudevsync]
[-p|--permission {r|rw}]
[-r|--readahead ReadAheadSectors|auto|none]
[-t|--test]
[--thinpool ThinPoolLogicalVolume[Path]]
[-v|--verbose]
[--version]
[PhysicalVolumePath...]
FAQ
-
What is the purpose of the lvcreate command in Linux?
The lvcreate command is used to create Logical Volumes (LVs) on Linux systems that utilize the Logical Volume Manager (LVM). LVM allows for efficient storage management by creating, resizing, and removing logical volumes without the need to repartition the physical disks.
-
How can I create a new logical volume using lvcreate?
To create a new logical volume, you need to specify the size, the name of the logical volume, and the volume group (VG) it will belong to. For example, to create a 10 GB logical volume named “my_logical_volume” in the volume group “my_volume_group”, you would use the command: sudo lvcreate -L 10G -n my_logical_volume my_volume_group.
-
How can I create a logical volume using a percentage of free space?
Instead of specifying an exact size, you can create a logical volume using a percentage of the available free space in the volume group. For example, to create a logical volume named “my_logical_volume” that uses 50% of the free space in the volume group “my_volume_group”, you would use the command: sudo lvcreate -l 50%FREE -n my_logical_volume my_volume_group.
-
What is a mirrored logical volume and how can I create one?
A mirrored logical volume is a type of logical volume that maintains multiple copies of the data for enhanced data protection. To create a 10 GB mirrored logical volume named “my_logical_volume” in the volume group “my_volume_group” with one mirror, you would use the command: sudo lvcreate -L 10G -m 1 -n my_logical_volume my_volume_group.
-
What is the meaning of the -l flag in the lvcreate command?
In the lvcreate command, the -l flag is used to specify the percentage of free space or the number of extents to use for the logical volume. This allows for more flexible management of storage space within a volume group.
