Add useful examples to create/resize a lvm[-thin] pool.

diff --git a/local-lvm.adoc b/local-lvm.adoc
index c5872befed40ebae98bee483ef0474cb2af3aea9..7c2a6cea9a0b4507bde5a540ce56dabdaf39fa00 100644 (file)
--- a/local-lvm.adoc
+++ b/local-lvm.adoc
@@ -40,6 +40,12 @@ 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 Logical Volume
+called ``data'' which is mounted at `/var/lib/vz`
+Starting from 4.2 the Logical Volume ``data'' is a LVM thin volume, used
+for block based storage of guest systems, and `/var/lib/vz` is simply a
+directory on the root file system.
+

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


@@ -57,3 +63,66 @@ 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''.
+
+First create a partition.
+
+ # sgdisk -N 1 /dev/sdb
+
+Create a **P**hysical **V**olumes (PV) without confirmation and 250K
+metadatasize.
+
+ # pvcreate --metadatasize 250k -y -ff /dev/sdb1
+
+Create a **V**olume **G**roup (VG) 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/data/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
+~~~~~~~~~~~~~~~~~~~~~~
+
+NOTE: When extending the data pool, the metadata pool must be extended with it.
+
+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>
+
+
+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