Name

vfs_shadow_copy2 — Expose snapshots to Windows clients as shadow copies.

Synopsis

vfs objects = shadow_copy2

DESCRIPTION

This VFS module is part of the samba(7) suite.

The vfs_shadow_copy2 VFS module functionality that is similar to Microsoft Shadow Copy services. When setup properly, this module allows Microsoft Shadow Copy clients to browse "shadow copies" on Samba shares.

This is a 2nd implementation of a shadow copy module. This version has the following features:

  1. You don't need to populate your shares with symlinks to the snapshots. This can be very important when you have thousands of shares, or use [homes].

  2. The inode number of the files is altered so it is different from the original. This allows the 'restore' button to work without a sharing violation.

This module is stackable.

CONFIGURATION

vfs_shadow_copy2 relies on a filesystem snapshot implementation. Many common filesystems have native support for this.

Filesystem snapshots must be mounted on specially named directories in order to be recognized by vfs_shadow_copy2. The snapshot mount points must be immediate children of a the directory being shared.

The snapshot naming convention is @GMT-YYYY.MM.DD-hh.mm.ss, where:

  • YYYY is the 4 digit year

  • MM is the 2 digit month

  • DD is the 2 digit day

  • hh is the 2 digit hour

  • mm is the 2 digit minute

  • ss is the 2 digit second.

The vfs_shadow_copy2 snapshot naming convention can be produced with the following date(1) command: 

	TZ=GMT date +@GMT-%Y.%m.%d-%H.%M.%S

OPTIONS

shadow:snapdir = SNAPDIR

Path to the directory where snapshots are kept.

shadow:basedir = BASEDIR

Path to the base directory that snapshots are from.

shadow:sort = asc/desc, or not specified for unsorted (default)

By this parameter one can specify that the shadow copy directories should be sorted before they are sent to the client. This can be beneficial as unix filesystems are usually not listed alphabetically sorted. If enabled, you typically want to specify descending order.

shadow:localtime = yes/no

This is an optional parameter that indicates whether the snapshot names are in UTC/GMT or in local time. By default UTC is expected.

shadow:format = format specification for snapshot names

This is an optional parameter that specifies the format specification for the naming of snapshots. The format must be compatible with the conversion specifications recognized by str[fp]time. The default value is "@GMT-%Y.%m.%d-%H.%M.%S".

shadow:fixinodes = yes/no

If you enable shadow:fixinodes then this module will modify the apparent inode number of files in the snapshot directories using a hash of the files path. This is needed for snapshot systems where the snapshots have the same device:inode number as the original files (such as happens with GPFS snapshots). If you don't set this option then the 'restore' button in the shadow copy UI will fail with a sharing violation.

EXAMPLES

Add shadow copy support to user home directories:

        [homes]
	vfs objects = shadow_copy2
	shadow:snapdir = /data/snapshots
	shadow:basedir = /data/home
	shadow:sort = desc

CAVEATS

This is not a backup, archival, or version control solution.

With Samba or Windows servers, vfs_shadow_copy2 is designed to be an end-user tool only. It does not replace or enhance your backup and archival solutions and should in no way be considered as such. Additionally, if you need version control, implement a version control system.

VERSION

This man page is correct for version 3.2.7 of the Samba suite.

AUTHOR

The original Samba software and related utilities were created by Andrew Tridgell. Samba is now developed by the Samba Team as an Open Source project similar to the way the Linux kernel is developed.