vzdump.adoc: use continuations

[pve-docs.git] / vzdump.adoc

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NAME
----

vzdump - Backup Utility for VMs and Containers 


SYNOPSYS
--------

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DESCRIPTION
-----------
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Backup and Restore
==================
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'vzdump' is a utility to make consistent snapshots of running virtual
machines (VMs). It basically creates an archive of the VM private
area, which also includes the VM configuration files. 'vzdump'
currently supports LXC containers and QemuServer VMs.

There are several ways to provide consistency (option `mode`):

`stop` mode::

Stop the VM during backup. This results in a very long downtime.

`suspend` mode::

For containers, this mode uses rsync to copy the container data to a temporary
location (see option `--tmpdir`). Then the container is suspended and a second
rsync copies changed files. After that, the container is started (resumed)
again. This results in minimal downtime, but needs additional space
to hold the container copy.
+
When the container is on a local filesystem and the target storage of the backup
is an NFS server, you should set `--tmpdir` to reside on a local filesystem too,
as this will result in a many fold performance improvement.
Use of a local `tmpdir` is also required if you want to backup in `suspend`
mode a local container using ACLs to an NFS server.
+
For QemuServer, this mode will suspend the VM, start
a live backup, and resume the VM. This does not require a temporary
storage.

`snapshot` mode::

For containers, this mode uses the snapshotting facilities of the
underlying storage. A snapshot will be made of the container volume,
and the snapshot content will be archived in a tar file.
+
For QemuServer, this mode will do a live backup similar to the
`suspend` mode, but without suspending/resuming the VM.

A technical overview of the Proxmox VE live backup for QemuServer can
be found online
https://git.proxmox.com/?p=pve-qemu-kvm.git;a=blob;f=backup.txt[here],

Backup File Names
-----------------

Newer versions of vzdump encode the virtual machine type and the
backup time into the filename, for example

 vzdump-lxc-105-2009_10_09-11_04_43.tar

That way it is possible to store several backup in the same
directory. The parameter `maxfiles` can be used to specify the
maximum number of backups to keep.

Restore
-------

The resulting archive files can be restored with the following programs.


`pct restore`:: Container restore utility

`qmrestore`:: QemuServer restore utility

For details see the corresponding manual pages.

Configuration
-------------

Global configuration is stored in '/etc/vzdump.conf'.

 tmpdir: DIR
 dumpdir: DIR
 storage: STORAGE_ID
 mode: snapshot|suspend|stop
 bwlimit: KBPS
 ionize: PRI
 lockwait: MINUTES
 stopwait: MINUTES
 size: MB
 maxfiles: N
 script: FILENAME
 exclude-path: PATHLIST

Hook Scripts
------------

You can specify a hook script with option `--script`. This script is
called at various phases of the backup process, with parameters
accordingly set. You can find an example in the documentation
directory ('vzdump-hook-script.pl').

File Exclusions
---------------

First, this option is only available for container backups. 'vzdump'
skips the following files with option `--stdexcludes`

 /var/log/?*
 /tmp/?*
 /var/tmp/?*
 /var/run/?*pid

Or you can manually specify exclude paths, for example:

 # vzdump 777 --exclude-path /tmp/ --exclude-path '/var/foo*'

(only excludes tmp directories)

Configuration files are also stored inside the backup archive
(`/etc/vzdump/`), and will be correctly restored.

Examples
--------

Simply dump VM 777 - no snapshot, just archive the VM private area and
configuration files to the default dump directory (usually
'/var/liv//vz/dump/').

 # vzdump 777

Use rsync and suspend/resume to create a snapshot (minimal downtime).

 # vzdump 777 --mode suspend

Backup all VMs and send notification mails to root and admin.

 # vzdump --all --mode suspend --mailto root --mailto admin

Use snapshot mode (no downtime).

 # vzdump 777 --dumpdir /mnt/backup --mode snapshot

Backup more than one VM (selectively)

 # vzdump 101 102 103 --mailto root

Backup all VMs excluding VM 101 and 102

 # vzdump --mode suspend --exclude 101,102

Restore a container to a new VM 600

 # pct restore 600 /mnt/backup/vzdump-lxc-777.tar

Restore a Qemu/KVM machine to VM 601

 # qmrestore /mnt/backup/vzdump-qemu-888.vma 601

Clone an existing container 101 to a new container 300 with a 4GB root
file system, using pipes

 # vzdump 101 --stdout | pct restore --rootfs 4 300 -


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