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vzdump.adoc: improve backup mode descriptions

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Dietmar Maurer 2016-04-14 08:55:12 +02:00
parent c31f32a9c1
commit 01d37422cd
1 changed files with 36 additions and 19 deletions
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@ -25,12 +25,39 @@ Backup and Restore
include::attributes.txt[]
endif::manvolnum[]
'vzdump' is a utility to make consistent snapshots 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.
'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.
There are several ways to provide consistency (option `mode`):
.Backup `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
https://git.proxmox.com/?p=pve-qemu-kvm.git;a=blob;f=backup.txt[here],
.Backup `mode` for Containers:
`stop` mode::
@ -38,7 +65,7 @@ Stop the guest 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
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
@ -49,23 +76,13 @@ 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.
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.
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
-----------------