improve docs about default storage configuration

[pve-docs.git] / pvesm.adoc

diff --git a/pvesm.adoc b/pvesm.adoc
index f0eb9b9d9f451684ecdbb4711fa8b8e86ea78914..5f8020e895a4ebdd5aee5a35cfaee4004d4f421d 100644 (file)
--- a/pvesm.adoc
+++ b/pvesm.adoc
@@ -83,6 +83,31 @@ snapshots and clones.
 TIP: It is possible to use LVM on top of an iSCSI storage. That way
 you get a 'shared' LVM storage.
 
+Thin provisioning
+~~~~~~~~~~~~~~~~~
+
+A number of storages, and the Qemu image format `qcow2`, support _thin
+provisioning_.  With thin provisioning activated, only the blocks that
+the guest system actually use will be written to the storage.
+
+Say for instance you create a VM with a 32GB hard disk, and after
+installing the guest system OS, the root filesystem of the VM contains
+3 GB of data.  In that case only 3GB are written to the storage, even
+if the guest VM sees a 32GB hard drive. In this way thin provisioning
+allows you to create disk images which are larger than the currently
+available storage blocks. You can create large disk images for your
+VMs, and when the need arises, add more disks to your storage without
+resizing the VMs filesystems.
+
+All storage types which have the 'Snapshots' feature also support thin
+provisioning.
+
+CAUTION: If a storage runs full, all guests using volumes on that
+storage receives IO error. This can cause file system inconsistencies
+and may corrupt your data. So it is advisable to avoid
+over-provisioning of your storage resources, or carefully observe
+free space to avoid such conditions.
+
 Storage Configuration
 ---------------------
 
@@ -109,24 +134,33 @@ Each storage pool has a `<type>`, and is uniquely identified by its `<STORAGE_ID
        ...
 ----
 
-NOTE: There is one special local storage pool named `local`. It refers to
-the directory '/var/lib/vz' and is automatically generated at installation
-time.
-
 The `<type>: <STORAGE_ID>` line starts the pool definition, which is then
 followed by a list of properties. Most properties have values, but some of
 them come with reasonable default. In that case you can omit the value.
 
+To be more specific, take a look at the default storage configuration
+after installation. It contains one special local storage pool named
+`local`, which refers to the directory '/var/lib/vz' and is always
+available. The {pve} installer creates additional storage entries
+depending on the storage type chosen at installation time.
+
 .Default storage configuration ('/etc/pve/storage.cfg')
 ----
 dir: local
        path /var/lib/vz
        content iso,vztmpl,backup
 
+# default image store on LVM based installation
 lvmthin: local-lvm
        thinpool data
        vgname pve
        content rootdir,images
+
+# default image store on ZFS based installation
+zfspool: local-zfs
+       pool rpool/data
+       sparse
+       content images,rootdir
 ----
 
 Common Storage Properties
@@ -308,6 +342,32 @@ Show filesystem path for a volume
 
  pvesm path <VOLUME_ID>
 
+ifdef::wiki[]
+
+See Also
+--------
+
+* link:/index.php/Storage:_Directory[Storage: Directory]
+
+* link:/index.php/Storage:_GlusterFS[Storage: GlusterFS]
+
+* link:/index.php/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
+
+* link:/index.php/Storage:_iSCSI[Storage: iSCSI]
+
+* link:/index.php/Storage:_LVM[Storage: LVM]
+
+* link:/index.php/Storage:_LVM_Thin[Storage: LVM Thin]
+
+* link:/index.php/Storage:_NFS[Storage: NFS]
+
+* link:/index.php/Storage:_RBD[Storage: RBD]
+
+* link:/index.php/Storage:_ZFS[Storage: ZFS]
+
+
+endif::wiki[]
+
 ifndef::wiki[]
 
 // backend documentation