From 01d37422cdc89fabfa36a06ba05044eb51eafb66 Mon Sep 17 00:00:00 2001 From: Dietmar Maurer Date: Thu, 14 Apr 2016 08:55:12 +0200 Subject: [PATCH] vzdump.adoc: improve backup mode descriptions --- vzdump.adoc | 55 +++++++++++++++++++++++++++++++++++------------------ 1 file changed, 36 insertions(+), 19 deletions(-) diff --git a/vzdump.adoc b/vzdump.adoc index a5a9ebf..ad4259c 100644 --- a/vzdump.adoc +++ b/vzdump.adoc @@ -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 ----------------- -- 2.39.2