Merge branch 'edited' of https://github.com/clayt0nk/qubes-doc into clayt0nk-edited

doc.md

@@ -66,6 +66,7 @@ Core documentation for Qubes users.
  * [Installing and Updating Software in Dom0](/doc/software-update-dom0/)
  * [Installing and Updating Software in DomUs](/doc/software-update-domu/)
  * [Backup, Restoration, and Migration](/doc/backup-restore/)
+ * [Volume Backup and Revert](/doc/volume-backup-revert/)
  * [DisposableVMs](/doc/disposablevm/)
  * [Block (or Storage) Devices](/doc/block-devices/)
  * [USB Devices](/doc/usb-devices)

user/common-tasks/volume-backup-revert.md

@@ -0,0 +1,45 @@
+---
+layout: doc
+title: Volume Backup and Revert
+permalink: /doc/volume-backup-revert/
+redirect_from:
+- /en/doc/volume-backup-revert/
+- /doc/VolumeBackupRevert/
+- /wiki/VolumeBackupRevert/
+---
+
+Qubes Volume Backup and Revert
+==============================
+
+With Qubes, it is possible to revert one of a VM's storage volumes to a previous
+state using the automatic snapshot that is normally saved every time a VM is
+shutdown. (Note that this is a different, lower level activity than the
+[Backup, Restoration, and Migration](/doc/backup-restore/) process.)
+
+In Qubes, when you create a new VM, it's volumes are stored in one of the
+system's [Storage Pools](/doc/storage-pools/). On pool creation, a
+revisions_to_keep default value is set for the entire pool. (For a pool creation
+example, see [Storing AppVMs on Secondary Drives](/doc/secondary-storage/).)
+Thereafter, each volume associated with a VM that is stored in this pool
+inherits the pool default revisions_to_keep.
+
+For the private volume associated with a VM named vmname, you may inspect the
+value of revisions_to_keep from the dom0 CLI as follows:
+
+    qvm-volume info vmname:private
+
+The output of the above command will also display the "Available revisions 
+(for revert)" at the bottom. For a very large volume in a small pool,
+revisions_to_keep should probably be set to the minimum value of 1 to minimize
+the possibility of the pool being accidentally filled up by snapshots. For a
+smaller volume for which you would like to have the future option of reverting, 
+revisions_to_keep should probably be set to at least 2. To set
+revisions_to_keep for this same VM / volume example:
+
+    qvm-volume config vmname:private revisions_to_keep 2
+
+With the VM stopped, you may revert to an older snapshot of the private volume
+from the the above list of "Available revisions (for revert)", where the last
+item on the list with the largest integer is the most recent snapshot:
+
+    qvm-volume revert vmname:private <revision>