[pve-devel] [PATCH v2 pve-docs] Add useful examples to create/resize a lvm[-thin] pool.

[Wolfgang Link]

---
 local-lvm.adoc | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/local-lvm.adoc b/local-lvm.adoc
index 45e875f..603e23d 100644
--- a/local-lvm.adoc
+++ b/local-lvm.adoc
@@ -41,6 +41,12 @@ 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.
 
+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
 ~~~~~~~~
 
@@ -58,3 +64,60 @@ 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.
+
+
+Creating a Volume Group
+~~~~~~~~~~~~~~~~~~~~~
+
+Let's assume we have an empty disk /dev/sdb, onto which we want to make a Volume Group named vmdata.
+
+First create a partition.
+
+ # sgdisk -N 1 /dev/sdb
+
+ #pvcreate --metadatasize 250k -y -ff /dev/sdb1
+
+ #vgcreate vmdata /dev/sdb1
+
+
+Creating an extra LV for /var/lib/vz
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+This can be easily done by create a new thin LV.
+
+ # lvcreate -n <Name> -V <Size[M,G,T]> <VG>/<LVThin_pool>
+
+A real world example might look.
+
+ # lvcreate -n vz -V 10G pve/data
+
+Now a filesystem must be create on the LV.
+
+ # mkfs.ext4 /dev/data/vz
+
+And at last step this have 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 at '/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
-- 
2.1.4