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188b4dc562
The path component following /dev/ should be the volume group where the thin pool exists, not the name of the thin pool itself. (the fstab example underneath has this right)
138 lines
3.5 KiB
Plaintext
138 lines
3.5 KiB
Plaintext
Logical Volume Manager (LVM)
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----------------------------
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ifdef::wiki[]
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:pve-toplevel:
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endif::wiki[]
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Most people install {pve} directly on a local disk. The {pve}
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installation CD offers several options for local disk management, and
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the current default setup uses LVM. The installer let you select a
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single disk for such setup, and uses that disk as physical volume for
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the **V**olume **G**roup (VG) `pve`. The following output is from a
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test installation using a small 8GB disk:
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----
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# pvs
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PV VG Fmt Attr PSize PFree
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/dev/sda3 pve lvm2 a-- 7.87g 876.00m
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# vgs
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VG #PV #LV #SN Attr VSize VFree
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pve 1 3 0 wz--n- 7.87g 876.00m
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----
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The installer allocates three **L**ogical **V**olumes (LV) inside this
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VG:
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----
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# lvs
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LV VG Attr LSize Pool Origin Data% Meta%
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data pve twi-a-tz-- 4.38g 0.00 0.63
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root pve -wi-ao---- 1.75g
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swap pve -wi-ao---- 896.00m
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----
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root:: Formatted as `ext4`, and contains the operation system.
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swap:: Swap partition
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data:: This volume uses LVM-thin, and is used to store VM
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images. LVM-thin is preferable for this task, because it offers
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efficient support for snapshots and clones.
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For {pve} versions up to 4.1, the installer creates a standard logical
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volume called ``data'', which is mounted at `/var/lib/vz`.
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Starting from version 4.2, the logical volume ``data'' is a LVM-thin pool,
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used to store block based guest images, and `/var/lib/vz` is simply a
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directory on the root file system.
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Hardware
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~~~~~~~~
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We highly recommend to use a hardware RAID controller (with BBU) for
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such setups. This increases performance, provides redundancy, and make
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disk replacements easier (hot-pluggable).
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LVM itself does not need any special hardware, and memory requirements
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are very low.
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Bootloader
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~~~~~~~~~~
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We install two boot loaders by default. The first partition contains
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the standard GRUB boot loader. The second partition is an **E**FI **S**ystem
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**P**artition (ESP), which makes it possible to boot on EFI systems.
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Creating a Volume Group
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~~~~~~~~~~~~~~~~~~~~~~~
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Let's assume we have an empty disk `/dev/sdb`, onto which we want to
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create a volume group named ``vmdata''.
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CAUTION: Please note that the following commands will destroy all
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existing data on `/dev/sdb`.
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First create a partition.
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# sgdisk -N 1 /dev/sdb
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Create a **P**hysical **V**olume (PV) without confirmation and 250K
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metadatasize.
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# pvcreate --metadatasize 250k -y -ff /dev/sdb1
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Create a volume group named ``vmdata'' on `/dev/sdb1`
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# vgcreate vmdata /dev/sdb1
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Creating an extra LV for `/var/lib/vz`
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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This can be easily done by creating a new thin LV.
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# lvcreate -n <Name> -V <Size[M,G,T]> <VG>/<LVThin_pool>
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A real world example:
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# lvcreate -n vz -V 10G pve/data
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Now a filesystem must be created on the LV.
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# mkfs.ext4 /dev/pve/vz
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At last this has to be mounted.
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WARNING: be sure that `/var/lib/vz` is empty. On a default
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installation it's not.
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To make it always accessible add the following line in `/etc/fstab`.
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# echo '/dev/pve/vz /var/lib/vz ext4 defaults 0 2' >> /etc/fstab
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Resizing the thin pool
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~~~~~~~~~~~~~~~~~~~~~~
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Resize the LV and the metadata pool can be achieved with the following
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command.
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# lvresize --size +<size[\M,G,T]> --poolmetadatasize +<size[\M,G]> <VG>/<LVThin_pool>
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NOTE: When extending the data pool, the metadata pool must also be
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extended.
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Create a LVM-thin pool
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~~~~~~~~~~~~~~~~~~~~~~
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A thin pool has to be created on top of a volume group.
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How to create a volume group see Section LVM.
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# lvcreate -L 80G -T -n vmstore vmdata
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