From 21592190f5f038c8c97e8c515e23741718404a39 Mon Sep 17 00:00:00 2001 From: Stefan Metzmacher Date: Thu, 22 Apr 2004 15:33:16 +0000 Subject: This is the documantation for the shadow_copy vfs module. Many thanks to Ed Riddle ('enigma' on #samba-technical) who wrotes the documentation for this module. metze (This used to be commit e2600d75103e576458f4c77dfc5410c73e3d4020) --- docs/howto/VFS.xml | 293 ++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 289 insertions(+), 4 deletions(-) (limited to 'docs/howto') diff --git a/docs/howto/VFS.xml b/docs/howto/VFS.xml index 0399cf011b..5dec637cd6 100644 --- a/docs/howto/VFS.xml +++ b/docs/howto/VFS.xml @@ -6,6 +6,7 @@ SimoSorceoriginal vfs_skel README AlexanderBokovoyoriginal vfs_netatalk docs StefanMetzmacherUpdate for multiple modules + EdRiddleoriginal shadow_copy docs Stackable VFS modules @@ -93,10 +94,10 @@ This can be done using a configuration similar to the one shown in - share - connect/disconnect - directory opens/create/remove - file open/close/rename/unlink/chmod + share + connect/disconnect + directory opens/create/remove + file open/close/rename/unlink/chmod @@ -245,6 +246,290 @@ This can be done using a configuration similar to the one shown in + + shadow_copy + + + THIS IS NOT A BACKUP, ARCHIVAL, OR VERSION CONTROL + SOLUTION! + + 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. + + + 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 + here.. + 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 from + the Microsoft's site. + + 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 example purposes + only. You need to make sure the LVM implementation + you choose to deploy is ready for production. Make sure you + do plenty of tests. + + Here are some common resources for LVM and EVMS: + + + Sistina's + LVM1 and LVM2 + + + Enterprise + Volume Management System (EVMS) + + + The LVM HOWTO + + + + See Learning + Linux LVM, Part 1 and Learning + Linux LWM, Part 2 for Daniel Robbins' well + written a two part tutorial on Linux and LVM using LVM + source code and reiserfs. + + + + + Shadow Copy Setup + + 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. + + + + Installed Operating System + + In my tests, I used Debian + Sarge (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. + + + + + Install & Configure Samba + + See the installation + section 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. + + + + + Install & Configure LVM + + 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. + + + + 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. + + + 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 + apt-get update && apt-get install + lvm10 devfsd xfsprogs should do the trick + for this example. + + + + 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. + + 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 modprobe lvm-mod + and set your system up to load it on + reboot by adding it to + (/etc/modules). + + + + Create the physical volume with pvcreate + /dev/hdb1 + + + + Create the volume group with and add /dev/hda1 to it + with vgcreate shadowvol /dev/hdb1 + + + You can use vgdisplay to review + information about the volume group. + + + + Now you can create the logical volume with something + like lvcreate -L400M -nsh_test + shadowvol + + 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 + /dev/shadowvol. + + + + Now we should be ready to format the logical volume + we named sh_test with mkfs.xfs + /dev/shadowvol/sh_test + + 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. + + Now we have an LVM volume where we can play with the + shadow_copy VFS module. + + + + Now we need to prepare the directory with something + like mkdir -p /data/shadow_share + 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 chmod 777 /data/shadow_share + and tighten the permissions once you get things + working. + + + + Mount the LVM volume using something like + mount /dev/shadowvol/sh_test + /data/shadow_share + + You may also want to edit your + /etc/fstab so that this + partition mounts during the system boot. + + + + + + Install & Configure the shadow_copy VFS + Module + + 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: + + + + Share With shadow_copy VFS + [shadow_share] + commentShadow Copy Enabled Share + path/data/shadow_share + vfs objectsshadow_copy + writeableyes + browseableyes + + + + + + Create Snapshots and Make Them Available to shadow_copy.so + + 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. + + + Here is a simple script used to create and mount the + snapshots: + +#!/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 + + Note that the script does not handle other things like + remounting snapshots on reboot. + + + + + Test From Client + + To test, you will need to install the shadow copy + client which you can obtain from the Microsoft + web site. 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. + + + + + + -- cgit