Fix path to block device when creating a file system on a thin volume

[pve-docs.git] / local-lvm.adoc

diff --git a/local-lvm.adoc b/local-lvm.adoc
index cdc0ef18418dc5c3cc54f67814db7c54f6f82e15..1abd6fc3f613e8381c56621eb28039a3b0a4ccaa 100644 (file)
--- a/local-lvm.adoc
+++ b/local-lvm.adoc
@@ -1,12 +1,14 @@
 Logical Volume Manager (LVM)
 ----------------------------
 Logical Volume Manager (LVM)
 ----------------------------

-include::attributes.txt[]
+ifdef::wiki[]
+:pve-toplevel:
+endif::wiki[]

 
 Most people install {pve} directly on a local disk. The {pve}
 installation CD offers several options for local disk management, and
 the current default setup uses LVM. The installer let you select a
 single disk for such setup, and uses that disk as physical volume for
 
 Most people install {pve} directly on a local disk. The {pve}
 installation CD offers several options for local disk management, and
 the current default setup uses LVM. The installer let you select a
 single disk for such setup, and uses that disk as physical volume for

-the **V**olume **G**roup (VG) 'pve'. The following output is from a
+the **V**olume **G**roup (VG) `pve`. The following output is from a

 test installation using a small 8GB disk:
 
 ----
 test installation using a small 8GB disk:
 
 ----


@@ -30,7 +32,7 @@ VG:
   swap pve  -wi-ao---- 896.00m     
 ----
 
   swap pve  -wi-ao---- 896.00m     
 ----
 

-root:: Formatted as 'ext4', and contains the operation system.
+root:: Formatted as `ext4`, and contains the operation system.

 
 swap:: Swap partition
 
 
 swap:: Swap partition
 


@@ -38,6 +40,13 @@ data:: This volume uses LVM-thin, and is used to store VM
 images. LVM-thin is preferable for this task, because it offers
 efficient support for snapshots and clones.
 
 images. LVM-thin is preferable for this task, because it offers
 efficient support for snapshots and clones.
 

+For {pve} versions up to 4.1, the installer creates a standard logical
+volume called ``data'', which is mounted at `/var/lib/vz`.
+
+Starting from version 4.2, the logical volume ``data'' is a LVM-thin pool,
+used to store block based guest images, and `/var/lib/vz` is simply a
+directory on the root file system.
+

 Hardware
 ~~~~~~~~
 
 Hardware
 ~~~~~~~~
 


@@ -55,3 +64,74 @@ Bootloader
 We install two boot loaders by default. The first partition contains
 the standard GRUB boot loader. The second partition is an **E**FI **S**ystem
 **P**artition (ESP), which makes it possible to boot on EFI systems.
 We install two boot loaders by default. The first partition contains
 the standard GRUB boot loader. The second partition is an **E**FI **S**ystem
 **P**artition (ESP), which makes it possible to boot on EFI systems.

+
+
+Creating a Volume Group
+~~~~~~~~~~~~~~~~~~~~~~~
+
+Let's assume we have an empty disk `/dev/sdb`, onto which we want to
+create a volume group named ``vmdata''.
+
+CAUTION: Please note that the following commands will destroy all
+existing data on `/dev/sdb`.
+
+First create a partition.
+
+ # sgdisk -N 1 /dev/sdb
+
+
+Create a **P**hysical **V**olume (PV) without confirmation and 250K
+metadatasize.
+
+ # pvcreate --metadatasize 250k -y -ff /dev/sdb1
+
+
+Create a volume group named ``vmdata'' on `/dev/sdb1`
+
+ # vgcreate vmdata /dev/sdb1
+
+
+Creating an extra LV for `/var/lib/vz`
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This can be easily done by creating a new thin LV.
+
+ # lvcreate -n <Name> -V <Size[M,G,T]> <VG>/<LVThin_pool>
+
+A real world example:
+
+ # lvcreate -n vz -V 10G pve/data
+
+Now a filesystem must be created on the LV.
+
+ # mkfs.ext4 /dev/pve/vz
+
+At last this has to be mounted.
+
+WARNING: be sure that `/var/lib/vz` is empty. On a default
+installation it's not.
+
+To make it always accessible add the following line in `/etc/fstab`.
+
+ # echo '/dev/pve/vz /var/lib/vz ext4 defaults 0 2' >> /etc/fstab
+
+
+Resizing the thin pool
+~~~~~~~~~~~~~~~~~~~~~~
+
+Resize the LV and the metadata pool can be achieved with the following
+command.
+
+ # lvresize --size +<size[\M,G,T]> --poolmetadatasize +<size[\M,G]> <VG>/<LVThin_pool>
+
+NOTE: When extending the data pool, the metadata pool must also be
+extended.
+
+
+Create a LVM-thin pool
+~~~~~~~~~~~~~~~~~~~~~~
+
+A thin pool has to be created on top of a volume group.
+How to create a volume group see Section LVM.
+
+ # lvcreate -L 80G -T -n vmstore vmdata