fix typo

[pve-docs.git] / vzdump.adoc

diff --git a/vzdump.adoc b/vzdump.adoc
index fc4246807b900fc5dd51aaa1ead6ab81b867a9a7..42383be011734640141df0abc250cfa6c994c40d 100644 (file)
--- a/vzdump.adoc
+++ b/vzdump.adoc
@@ -25,40 +25,64 @@ Backup and Restore
 include::attributes.txt[]
 endif::manvolnum[]
 
-'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.
+'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::
 
-Stop the VM during backup. This results in a very long downtime.
+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::
 
-For containers, this mode uses rsync to copy the VM data to a temporary
-location (see option `--tmpdir`). Then the VM is suspended and a second
-rsync copies changed files. After that, the VM is started (resumed)
-again. This results in minimal downtime, but needs additional space
-to hold the VM copy.
-
-For QemuServer, this mode will suspend the VM, start
-a live backup, and resume the VM.
+This mode does not really make sense for qemu. Please use snapshot
+mode instead.
 
 `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 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],
+https://git.proxmox.com/?p=pve-qemu-kvm.git;a=blob;f=backup.txt[here].
+
+
+.Backup `mode` for Containers:
+
+`stop` mode::
+
+Stop the guest during backup. This 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 in `suspend`
+mode a local container using ACLs to an NFS server.
+
+`snapshot` mode::
+
+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.
+
 
 Backup File Names
 -----------------
@@ -133,7 +157,7 @@ Configuration files are also stored inside the backup archive
 Examples
 --------
 
-Simply dump VM 777 - no snapshot, just archive the VM private area and
+Simply dump guest 777 - no snapshot, just archive the guest private area and
 configuration files to the default dump directory (usually
 '/var/liv//vz/dump/').
 
@@ -143,7 +167,7 @@ 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.
+Backup all guest systems and send notification mails to root and admin.
 
  # vzdump --all --mode suspend --mailto root --mailto admin
 
@@ -151,19 +175,19 @@ Use snapshot mode (no downtime).
 
  # vzdump 777 --dumpdir /mnt/backup --mode snapshot
 
-Backup more than one VM (selectively)
+Backup more than one guest (selectively)
 
  # vzdump 101 102 103 --mailto root
 
-Backup all VMs excluding VM 101 and 102
+Backup all guests excluding 101 and 102
 
  # vzdump --mode suspend --exclude 101,102
 
-Restore a container to a new VM 600
+Restore a container to a new CT 600
 
  # pct restore 600 /mnt/backup/vzdump-lxc-777.tar
 
-Restore a Qemu/KVM machine to VM 601
+Restore a QemuServer VM to VM 601
 
  # qmrestore /mnt/backup/vzdump-qemu-888.vma 601