vzdump-lxc-105-2009_10_09-11_04_43.tar
vzdump is a utility to make consistent backups of running guest
systems. It basically creates an archive of the guest private area,
which also includes the guest configuration files. vzdump currently
supports LXC containers and QemuServer VMs. There are several ways to
provide consistency (option mode
), depending on the guest type.
mode
for VMs:stop
mode
This first performns a clean shutdown of the VM to make sure it is stopped. It then starts the VM in suspended mode and uses the qemu backup feature to dump all data. If the VM was running, we start (resume) it immediately after starting the qemu backup task. This keeps the downtime as low as possible.
suspend
mode
This mode does not really make sense for qemu. Please use snapshot mode instead.
snapshot
mode
This mode simply starts a qemu live backup task. If the guest agent
is enabled (agent: 1
) and running, it calls guest-fsfreeze-freeze
and guest-fsfreeze-thaw to improve consistency.
A technical overview of the Proxmox VE live backup for QemuServer can be found online here.
|
Qemu backup provides snapshots on any storage type. It does not require that the underlying storage supports snapshots. |
mode
for Containers:stop
mode
Stop the container for the duration of the backup. This potentially results in a very long downtime.
suspend
mode
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 a local container
using ACLs in suspend mode if the backup storage is an NFS server.
snapshot
mode
This mode uses the snapshotting facilities of the underlying storage. First, the container will be suspended to ensure data consistency. A temporary snapshot of the container’s volumes will be made and the snapshot content will be archived in a tar file. Finally, the temporary snapshot is deleted again.
|
snapshot mode requires that all backed up volumes are on a storage that
supports snapshots. Using the backup=no mountpoint option individual volumes
can be excluded from the backup (and thus this requirement). |
|
bind and device mountpoints are skipped during backup operations, like volume mountpoints with the backup option disabled. |
Newer versions of vzdump encode the guest 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.
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.
Global configuration is stored in /etc/vzdump.conf. The file uses a simple colon separated key/value format. Each line has the following format:
OPTION: value
Blank lines in the file are ignored, and lines starting with a # character are treated as comments and are also ignored. Values from this file are used as default, and can be overwritten on the command line.
We currently support the following options:
bwlimit
: integer (0 - N)
(default=0
)
Limit I/O bandwidth (KBytes per second).
compress
: (0 | 1 | gzip | lzo)
(default=0
)
Compress dump file.
dumpdir
: string
Store resulting files to specified directory.
exclude-path
: string
Exclude certain files/directories (shell globs).
ionice
: integer (0 - 8)
(default=7
)
Set CFQ ionice priority.
lockwait
: integer (0 - N)
(default=180
)
Maximal time to wait for the global lock (minutes).
mailnotification
: (always | failure)
(default=always
)
Specify when to send an email
mailto
: string
Comma-separated list of email addresses that should receive email notifications.
maxfiles
: integer (1 - N)
(default=1
)
Maximal number of backup files per guest system.
mode
: (snapshot | stop | suspend)
(default=snapshot
)
Backup mode.
pigz
: integer
(default=0
)
Use pigz instead of gzip when N>0. N=1 uses half of cores, N>1 uses N as thread count.
remove
: boolean
(default=1
)
Remove old backup files if there are more than maxfiles backup files.
script
: string
Use specified hook script.
stdexcludes
: boolean
(default=1
)
Exclude temporary files and logs.
stopwait
: integer (0 - N)
(default=10
)
Maximal time to wait until a guest system is stopped (minutes).
storage
: string
Store resulting file to this storage.
tmpdir
: string
Store temporary files to specified directory.
tmpdir: /mnt/fast_local_disk
storage: my_backup_storage
mode: snapshot
bwlimit: 10000
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).
|
this option is only available for container backups. |
vzdump skips the following files by default (disable with the option
--stdexcludes 0
)
/tmp/?*
/var/tmp/?*
/var/run/?*pid
You can also manually specify (additional) 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
(in ./etc/vzdump/
) and will be correctly restored.
Simply dump guest 777 - no snapshot, just archive the guest private area and configuration files to the default dump directory (usually /var/lib/vz/dump/).
# vzdump 777
Use rsync and suspend/resume to create a snapshot (minimal downtime).
# vzdump 777 --mode suspend
Backup all guest systems and send notification mails to root and admin.
# vzdump --all --mode suspend --mailto root --mailto admin
Use snapshot mode (no downtime) and non-default dump directory.
# vzdump 777 --dumpdir /mnt/backup --mode snapshot
Backup more than one guest (selectively)
# vzdump 101 102 103 --mailto root
Backup all guests excluding 101 and 102
# vzdump --mode suspend --exclude 101,102
Restore a container to a new CT 600
# pct restore 600 /mnt/backup/vzdump-lxc-777.tar
Restore a QemuServer VM 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 -