<author><firstname>Simo</firstname><surname>Sorce</surname><contrib>original vfs_skel README</contrib></author>
<author><firstname>Alexander</firstname><surname>Bokovoy</surname><contrib>original vfs_netatalk docs</contrib></author>
<author><firstname>Stefan</firstname><surname>Metzmacher</surname><contrib>Update for multiple modules</contrib></author>
+ <author><firstname>Ed</firstname><surname>Riddle</surname><contrib>original shadow_copy docs</contrib></author>
</chapterinfo>
<title>Stackable VFS modules</title>
A simple module to audit file access to the syslog
facility. The following operations are logged:
<itemizedlist>
- <listitem>share</listitem>
- <listitem>connect/disconnect</listitem>
- <listitem>directory opens/create/remove</listitem>
- <listitem>file open/close/rename/unlink/chmod</listitem>
+ <listitem><para>share</para></listitem>
+ <listitem><para>connect/disconnect</para></listitem>
+ <listitem><para>directory opens/create/remove</para></listitem>
+ <listitem><para>file open/close/rename/unlink/chmod</para></listitem>
</itemizedlist>
</para>
</sect2>
+ <sect2>
+ <title>shadow_copy</title>
+ <warning>
+ <para>
+ <emphasis>THIS IS NOT A BACKUP, ARCHIVAL, OR VERSION CONTROL
+ SOLUTION!</emphasis></para>
+ <para>
+ With Samba or Windows servers, shadow copy 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. You have been
+ warned.</para>
+ </warning>
+ <para>
+ The shadow_copy module allows you to setup functionality that
+ is similar to MS shadow copy services. When setup properly,
+ this module allows Microsoft shadow copy clients to browse
+ "shadow copies" on samba shares. You will need to install the
+ shadow copy client. You can get the MS shadow copy client
+ <ulink noescape="1"
+ url="http://www.microsoft.com/windowsserver2003/downloads/shadowcopyclient.mspx">here.</ulink>.
+ Note the additional requirements for pre-Windows XP clients.
+ I did not test this functionality with any pre-Windows XP
+ clients. You should be able to get more information about MS
+ Shadow Copy <ulink noescape="1"
+ url="http://www.microsoft.com/windowsserver2003/techinfo/overview/scr.mspx">from
+ the Microsoft's site</ulink>.</para>
+ <para>
+ The shadow_copy VFS module requires some underlying file system
+ setup with some sort of Logical Volume Manager (LVM) such as
+ LVM1, LVM2, or EVMS. Setting up LVM is beyond the scope of
+ this document; however, we will outline the steps we took to
+ test this functionality for <emphasis>example purposes
+ only.</emphasis> You need to make sure the LVM implementation
+ you choose to deploy is ready for production. Make sure you
+ do plenty of tests.</para>
+ <para>
+ Here are some common resources for LVM and EVMS:
+ <itemizedlist>
+ <listitem>
+ <para><ulink noescape="1"
+ url="http://www.sistina.com/products_lvm_download.htm">Sistina's
+ LVM1 and LVM2</ulink></para>
+ </listitem>
+ <listitem>
+ <para><ulink url="http://evms.sourceforge.net/">Enterprise
+ Volume Management System (EVMS)</ulink></para>
+ </listitem>
+ <listitem>
+ <para><ulink url="http://tldp.org/HOWTO/LVM-HOWTO/">The LVM HOWTO</ulink></para>
+ </listitem>
+ <listitem>
+ <para>
+ See <ulink
+ url="http://www-106.ibm.com/developerworks/linux/library/l-lvm/">Learning
+ Linux LVM, Part 1</ulink> and <ulink
+ url="http://www-106.ibm.com/developerworks/library/l-lvm2.html">Learning
+ Linux LWM, Part 2</ulink> for Daniel Robbins' well
+ written a two part tutorial on Linux and LVM using LVM
+ source code and reiserfs.</para>
+ </listitem>
+ </itemizedlist>
+ </para>
+ <sect3>
+ <title>Shadow Copy Setup</title>
+ <para>
+ At the time of this writing, not much testing has been done.
+ I tested the shadow copy VFS module with a specific scenario
+ which was not deployed in a production environment, but more
+ as a proof of concept. The scenario involved a Samba 3 file
+ server on Debian Sarge with an XFS file system and LVM1. I
+ do NOT recommend you use this as a solution without doing
+ your own due diligence with regard to all the components
+ presented here. That said, following is an basic outline of
+ how I got things going.</para>
+ <orderedlist>
+ <listitem>
+ <formalpara>
+ <title>Installed Operating System </title>
+ <para>
+ In my tests, I used <ulink
+ url="http://www.debian.org/devel/debian-installer/">Debian
+ Sarge</ulink> (i.e. testing) on an XFS file system.
+ Setting up the OS is a bit beyond the scope of this
+ document. It is assumed that you have a working OS
+ capable of running Samba.</para>
+ </formalpara>
+ </listitem>
+ <listitem>
+ <formalpara>
+ <title>Install & Configure Samba</title>
+ <para>
+ See the <link linkend="introduction">installation
+ section</link> of this HOWTO for more detail on this.
+ It doesn't matter if it is a Domain Controller or
+ Member File Server, but it is assumed that you have a
+ working Samba 3.0.3 or newer server running.</para>
+ </formalpara>
+ </listitem>
+ <listitem>
+ <formalpara>
+ <title>Install & Configure LVM</title>
+ <para>
+ Before you can make shadow copies available to the
+ client, you have to create the shadow copies. This is
+ done by taking some sort of file system snapshot.
+ Snapshots are a typical feature of Logical Volume
+ Managers such as LVM, so we first need to have that
+ setup.</para>
+ </formalpara>
+ <itemizedlist>
+ <para>
+ The following is provided as an example and will be
+ most helpful for Debian users. Again, this was tested
+ using the "testing" or "Sarge" distribution.</para>
+ <listitem>
+ <para>
+ Install lvm10 and devfsd packages if you have not
+ done so already. On Debian systems, you are warned
+ of the interaction of devfs and lvm1 which requires
+ the use of devfs filenames. Running
+ <command>apt-get update && apt-get install
+ lvm10 devfsd xfsprogs</command> should do the trick
+ for this example.</para>
+ </listitem>
+ <listitem>
+ <para>
+ Now you need to create a volume. You will need to
+ create a partition (or partitions) to add to your
+ volume. Use your favorite partitioning tool
+ (e.g. Linux fdisk, cfdisk, etc.). The partition
+ type should be set to 0x8e for "Linux LVM." In this
+ example, we will use /dev/hdb1.</para>
+ <para>
+ Once you have the Linux LVM partition (type 0x8e),
+ you can run a series of commands to create the LVM
+ volume. You can use several disks and or
+ partitions, but we will use only one in this
+ example. You may also need to load the kernel
+ module with something like <command>modprobe lvm-mod
+ </command> and set your system up to load it on
+ reboot by adding it to
+ (<filename>/etc/modules</filename>). </para>
+ </listitem>
+ <listitem>
+ <para>
+ Create the physical volume with <command>pvcreate
+ /dev/hdb1</command></para>
+ </listitem>
+ <listitem>
+ <para>
+ Create the volume group with and add /dev/hda1 to it
+ with <command>vgcreate shadowvol /dev/hdb1</command>
+ </para>
+ <para>
+ You can use <command>vgdisplay</command> to review
+ information about the volume group.</para>
+ </listitem>
+ <listitem>
+ <para>
+ Now you can create the logical volume with something
+ like <command>lvcreate -L400M -nsh_test
+ shadowvol</command></para>
+ <para>
+ This creates the logical volume of 400MB's named
+ "sh_test" in the volume group we created called
+ shadowvol. If everything is working so far, you
+ should see them in
+ <filename>/dev/shadowvol</filename>.</para>
+ </listitem>
+ <listitem>
+ <para>
+ Now we should be ready to format the logical volume
+ we named sh_test with <command>mkfs.xfs
+ /dev/shadowvol/sh_test</command></para>
+ <para>
+ You can format the logical volume with any file
+ system you choose, but make sure to use one that
+ allows you to take advantage of the additional
+ features of LVM such as freezing, resizing and
+ growing your file systems.</para>
+ <para>
+ Now we have an LVM volume where we can play with the
+ shadow_copy VFS module.</para>
+ </listitem>
+ <listitem>
+ <para>
+ Now we need to prepare the directory with something
+ like <command>mkdir -p /data/shadow_share</command>
+ or whatever you want to name your shadow copy
+ enabled Samba share. Make sure you set the
+ permissions such that you can use it. If in doubt,
+ use <command>chmod 777 /data/shadow_share</command>
+ and tighten the permissions once you get things
+ working.</para>
+ </listitem>
+ <listitem>
+ <para>
+ Mount the LVM volume using something like
+ <command>mount /dev/shadowvol/sh_test
+ /data/shadow_share</command></para>
+ <para>
+ You may also want to edit your
+ <filename>/etc/fstab</filename> so that this
+ partition mounts during the system boot.</para>
+ </listitem>
+ </itemizedlist>
+ </listitem>
+ <listitem>
+ <formalpara>
+ <title>Install & Configure the shadow_copy VFS
+ Module</title>
+ <para>
+ Finally we get to the actual shadow_copy VFS module.
+ The shadow_copy VFS module should be available in
+ Samba 3.0.3 and higher. The smb.conf configuration is pretty
+ standard. Here is our example of a share configured
+ with the shadow_copy VFS module:</para>
+ </formalpara>
+ <para>
+ <smbconfexample id="vfsshadow">
+ <title>Share With shadow_copy VFS</title>
+ <smbconfsection>[shadow_share]</smbconfsection>
+ <smbconfoption><name>comment</name><value>Shadow Copy Enabled Share</value></smbconfoption>
+ <smbconfoption><name>path</name><value>/data/shadow_share</value></smbconfoption>
+ <smbconfoption><name>vfs objects</name><value>shadow_copy</value></smbconfoption>
+ <smbconfoption><name>writeable</name><value>yes</value></smbconfoption>
+ <smbconfoption><name>browseable</name><value>yes</value></smbconfoption>
+ </smbconfexample>
+ </para>
+ </listitem>
+ <listitem>
+ <formalpara>
+ <title>Create Snapshots and Make Them Available to shadow_copy.so</title>
+ <para>
+ Before you can browse the shadow copies, you must
+ create them and mount them. This will most likely be
+ done with a script that runs as a cron job. With this
+ particular solution, the shadow_copy VFS module is
+ used to browse LVM snapshots. Those snapshots are not
+ created by the module. They are not made available by
+ the module either. This module allows the shadow copy
+ enabled client to browse the snapshots you take and
+ make available.</para>
+ </formalpara>
+ <para>
+ Here is a simple script used to create and mount the
+ snapshots:
+ <screen>
+#!/bin/bash
+# This is a test, this is only a test
+SNAPNAME=`date +%Y.%m.%d-%H.%M.%S`
+xfs_freeze -f /data/shadow_share/
+lvcreate -L10M -s -n $SNAPNAME /dev/shadowvol/sh_test
+xfs_freeze -u /data/shadow_share/
+mkdir /data/shadow_share/@GMT-$SNAPNAME
+mount /dev/shadowvol/$SNAPNAME /data/shadow_share/@GMT-$SNAPNAME -onouuid,ro
+ </screen>
+ Note that the script does not handle other things like
+ remounting snapshots on reboot.
+ </para>
+ </listitem>
+ <listitem>
+ <formalpara>
+ <title>Test From Client</title>
+ <para>
+ To test, you will need to install the shadow copy
+ client which you can obtain from the <ulink
+ url="http://www.microsoft.com/windowsserver2003/downloads/shadowcopyclient.mspx">Microsoft
+ web site.</ulink> I only tested this with an XP client
+ so your results may vary with other pre-XP clients.
+ Once installed, with your XP client you can
+ right-click on specific files or in the empty space of
+ the shadow_share and view the "properties". If
+ anything has changed, then you will see it on the
+ "Previous Versions" tab of the properties
+ window. </para>
+ </formalpara>
+ </listitem>
+ </orderedlist>
+ </sect3>
+ </sect2>
+
</sect1>
<sect1>
git.samba.org / ira / wip.git / commitdiff