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8f40162150
mentioning why zeroing-out might be necessary. Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
105 lines
2.7 KiB
Plaintext
105 lines
2.7 KiB
Plaintext
[[storage_lvm]]
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LVM Backend
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-----------
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ifdef::wiki[]
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:pve-toplevel:
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:title: Storage: LVM
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endif::wiki[]
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Storage pool type: `lvm`
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LVM is a light software layer on top of hard disks and partitions. It
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can be used to split available disk space into smaller logical
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volumes. LVM is widely used on Linux and makes managing hard drives
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easier.
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Another use case is to put LVM on top of a big iSCSI LUN. That way you
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can easily manage space on that iSCSI LUN, which would not be possible
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otherwise, because the iSCSI specification does not define a
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management interface for space allocation.
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Configuration
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~~~~~~~~~~~~~
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The LVM backend supports the common storage properties `content`, `nodes`,
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`disable`, and the following LVM specific properties:
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`vgname`::
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LVM volume group name. This must point to an existing volume group.
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`base`::
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Base volume. This volume is automatically activated before accessing
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the storage. This is mostly useful when the LVM volume group resides
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on a remote iSCSI server.
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`saferemove`::
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Zero-out data when removing LVs. When removing a volume, this makes
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sure that all data gets erased and cannot be accessed by other LVs
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created later (which happen to be assigned the same physical extents).
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This is a costly operation, but may be required as a security measure
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in certain environments.
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`saferemove_throughput`::
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Wipe throughput (`cstream -t` parameter value).
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.Configuration Example (`/etc/pve/storage.cfg`)
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----
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lvm: myspace
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vgname myspace
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content rootdir,images
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----
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File naming conventions
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~~~~~~~~~~~~~~~~~~~~~~~
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The backend use basically the same naming conventions as the ZFS pool
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backend.
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vm-<VMID>-<NAME> // normal VM images
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Storage Features
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~~~~~~~~~~~~~~~~
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LVM is a typical block storage, but this backend does not support
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snapshots and clones. Unfortunately, normal LVM snapshots are quite
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inefficient, because they interfere with all writes on the entire volume
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group during snapshot time.
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One big advantage is that you can use it on top of a shared storage,
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for example, an iSCSI LUN. The backend itself implements proper cluster-wide
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locking.
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TIP: The newer LVM-thin backend allows snapshots and clones, but does
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not support shared storage.
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.Storage features for backend `lvm`
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[width="100%",cols="m,m,3*d",options="header"]
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|==============================================================================
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|Content types |Image formats |Shared |Snapshots |Clones
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|images rootdir |raw |possible |no |no
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|==============================================================================
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Examples
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~~~~~~~~
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List available volume groups:
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# pvesm lvmscan
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ifdef::wiki[]
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See Also
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~~~~~~~~
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* link:/wiki/Storage[Storage]
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endif::wiki[]
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