the cluster have direct access to VM disk images. There is no need to
copy VM image data, so live migration is very fast in that case.
-The storage library (package 'libpve-storage-perl') uses a flexible
+The storage library (package `libpve-storage-perl`) uses a flexible
plugin system to provide a common interface to all storage types. This
can be easily adopted to include further storage types in future.
|=========================================================
TIP: It is possible to use LVM on top of an iSCSI storage. That way
-you get a 'shared' LVM storage.
+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.
+~~~~~~~~~~~~~~~~~
+
+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
---------------------
All {pve} related storage configuration is stored within a single text
-file at '/etc/pve/storage.cfg'. As this file is within '/etc/pve/', it
+file at `/etc/pve/storage.cfg`. As this file is within `/etc/pve/`, it
gets automatically distributed to all cluster nodes. So all nodes
share the same storage configuration.
Sharing storage configuration make perfect sense for shared storage,
-because the same 'shared' storage is accessible from all nodes. But is
+because the same ``shared'' storage is accessible from all nodes. But is
also useful for local storage types. In this case such local storage
is available on all nodes, but it is physically different and can have
totally different content.
...
----
-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.
-.Default storage configuration ('/etc/pve/storage.cfg')
+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
backup:::
-Backup files ('vzdump').
+Backup files (`vzdump`).
iso:::
Volume Ownership
~~~~~~~~~~~~~~~~
-There exists an ownership relation for 'image' type volumes. Each such
+There exists an ownership relation for `image` type volumes. Each such
volume is owned by a VM or Container. For example volume
`local:230/example-image.raw` is owned by VM 230. Most storage
backends encodes this ownership information into the volume name.
allocation and removal of volumes is done by the VM and Container
management tools.
-Nevertheless, there is a command line tool called 'pvesm' ({pve}
-storage manager), which is able to perform common storage management
+Nevertheless, there is a command line tool called `pvesm` (``{pve}
+Storage Manager''), which is able to perform common storage management
tasks.
See Also
--------
-* link:/index.php/Storage:_Directory[Storage: Directory]
+* link:/wiki/Storage:_Directory[Storage: Directory]
-* link:/index.php/Storage:_GlusterFS[Storage: GlusterFS]
+* link:/wiki/Storage:_GlusterFS[Storage: GlusterFS]
-* link:/index.php/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
+* link:/wiki/Storage:_User_Mode_iSCSI[Storage: User Mode iSCSI]
-* link:/index.php/Storage:_iSCSI[Storage: iSCSI]
+* link:/wiki/Storage:_iSCSI[Storage: iSCSI]
-* link:/index.php/Storage:_LVM[Storage: LVM]
+* link:/wiki/Storage:_LVM[Storage: LVM]
-* link:/index.php/Storage:_LVM_Thin[Storage: LVM Thin]
+* link:/wiki/Storage:_LVM_Thin[Storage: LVM Thin]
-* link:/index.php/Storage:_NFS[Storage: NFS]
+* link:/wiki/Storage:_NFS[Storage: NFS]
-* link:/index.php/Storage:_RBD[Storage: RBD]
+* link:/wiki/Storage:_RBD[Storage: RBD]
-* link:/index.php/Storage:_ZFS[Storage: ZFS]
+* link:/wiki/Storage:_ZFS[Storage: ZFS]
endif::wiki[]
projects / pve-docs.git / blobdiff