Backup server config

Backup server configuration

Overview

Warning:

This is a non standard method of transferring data between servers and should be carefully used to ensure that no data is lost or altered during the process. If wrong or inappropriate copying procedures are used, your data may have incorrect permissions applied. Using tar and scp is the "best" way to transfer files directly between servers while retaining correct permissions/ownership in the process.

This method is a good way to create a server clone that has identical configuration but no data, without going through all the setup again.

This method utilizes the standard backup to desktop function and the restore from CD or USB disk at first startup function.

The non standard part of this procedure is that data in ibays and user folders and other specific locations, is temporarily moved to a newly created /temp folder, which will not be included in the backup (as /temp is not in the standard list of backup inclusions).

The main reason for doing this is to keep the resultant smeserver.tgz backup file size smaller than 2Gb, so that there are no problems doing a backup to desktop on a workstation using the http protocol and any browser.

If you also wish to transfer data, then user, ibay and other data in other specific locations can be manually copied from the backup server to the restored server either partially or in total after the restore. Use tar and scp to transfer this data so that correct permissions and ownership are retained, see the section "Copying data to the restored server".

If you have large amounts of data in other locations that will cause your backup file to exceed 2Gb, then that data should also be temporarily moved to the /temp folder, and manually copied to the new server after the restore.

	Note:
	With sme 7.2 or newer, it is possible to create a backup to desktop smeserver.tgz file of the order of 52Gb, when saved to a share or a connected drive formatted with a NTFS or ext3 file system and when using Firefox as the browser. See bug 81.

Procedure

	Note:
	This method does transfer mysql database information.

	Tip:
	It is preferable to make a /temp folder as files in /tmp are routinely automatically deleted by the system, and using /temp will avoid unwanted inadvertent deletion. If you don't have much data or email in /home/e-smith/files/users then don't bother to move that.

1. On the server to be backed up (server1) do mkdir -p /temp mv /home/e-smith/files/users /temp mv /home/e-smith/files/ibays /temp mv /home/e-smith/files/xxxx /temp
2. Perform backup to desktop on server1 using the standard server manager panel
3. Then on server1 do mv /temp/users /home/e-smith/files/ mv /temp/ibays /home/e-smith/files/ mv /temp/xxxx /home/e-smith/files/
4. Build another server to restore to (server2), and perform a fresh install of sme server on it. Note that any preferred hardware can be used, it does not need to be physically identical to the original server the backup was performed on.
5. Copy the smeserver.tgz backup file to a CD or attached USB disk. When you first start server2 after installing the fresh OS, you will be asked if you want to do a Restore. Select the appropriate source ie CD or USB. Note you only see this Restore option the first time your start the server2, so do not skip using this option as it will not be presented on future restarts.
6. After the restore is complete on server2, login as admin and select Configure this server. Change the local IP and other settings as required, detect different NIC's, and also change to server only mode if it's going to be a second server on your network (where the backed up server was a server/gateway) and disable the DHCP server. As a minimum, make sure you change the local IP on the restored server as it will be identically configured after the restore. Then log in to server manager on the restored server and change workgroup name and domain controller settings and any other settings required etc.

You should now have a second server (server2) which is identically configured to server1 (except for changes that were made) but without user and ibay data. Note that the user and ibays will exist in server manager and in the file structure, but they will be empty.

Copying data to the restored server

You can then optionally transfer the data across the network from server to server either totally or in limited form as required using command line, tar and scp. You can delete any users, ibays, groups and other settings not required on the restored server via server manager.

It is preferable to tar/untar data so you don't loose ownership and permissions during the copy from server1 to server2. If copying user data and email using normal copy commands, then ensure that ownership is correct on the new server.

Modify the following commands appropriately to only move the data you require.

1. Use tar to compress all the user and ibays folders (on server1) by doing cd /home/e-smith/files tar -czvf /temp/users.tar.gz users tar -czvf /temp/ibays.tar.gz ibays
2. Use scp to copy the tarred files between machines by doing (on server1)

   	Note:
   	You will need to have remote access between the servers setup to be able to ssh, either using passwords or ssh keys.

   
   

   scp /temp/users.tar.gz server2IP:/home/e-smith/files/
   scp /temp/ibays.tar.gz server2IP:/home/e-smith/files/ 
   

   If ssh is configured for a different port (than 22) use

   scp -P xxxx /temp/users.tar.gz server2IP:/home/e-smith/files/
   scp -P xxxx /temp/ibays.tar.gz server2IP:/home/e-smith/files/
   

   where xxxx = port number

3. Use tar to uncompress all the user and ibay folders by doing (on server2) cd /home/e-smith/files/ tar -xvzf users.tar.gz tar -xvzf ibays.tar.gz rm /home/e-smith/files/users.tar.gz rm /home/e-smith/files/ibays.tar.gz If required, to correct ownership for each user on server2 do cd /home/e-smith/files/users chown -R username:username username

Manually transferring configuration information

If you wish to manually transfer configuration information from an old server to a new server you can use the following steps. All the files listed below are required as user information & passwords is contained in many different locations.

On the old server do the following to dump the mysql tables to a file in /home/e-smith/db/mysql/:

signal-event pre-backup

Before restoring files to the new server, issue the following command on the new server:

signal-event pre-restore

Then copy all the following files & folders from the old server to the new server preferably using the tar command, see usage examples & syntax above in the section "Copying data to the restored server". You can exclude ibay & user data if preferred by moving that data to /temp (see steps in above section "Procedure") This list is based on the requirements of sme7.2:

/etc/e-smith/templates-custom
/etc/e-smith/templates-user-custom
/etc/group
/etc/gshadow
/etc/passwd
/etc/samba/secrets.tdb
/etc/samba/smbpasswd
/etc/shadow
/etc/smbpasswd
/etc/ssh
/etc/sudoers
/home/e-smith
/root

and add in

/opt

if you have stuff installed there.

After copying all the required files to the new server you then need to run the following commands on the new server:

signal-event post-upgrade
reboot

Standard backup & restore inclusions

This command will give a listing of the files & folders included in a standard backup & restore, as per a default install of sme server.

perl -e 'use esmith::Backup; $b = new esmith::Backup;print join("\n",$b->restore_list)'

Which on a sme7.3 server shows:

home/e-smith
etc/e-smith/templates-custom
etc/e-smith/templates-user-custom
etc/ssh
root
etc/sudoers
etc/passwd
etc/shadow
etc/group
etc/gshadow
etc/samba/secrets.tdb
etc/samba/smbpasswd
etc/smbpasswd

All files/scripts associated with the standard backup and restore processes can be found with this command.

rpm -ql e-smith-backup

The inclusion list can be found in

/usr/lib/perl5/site_perl/esmith/Backup.pm

Changes to this file will be overwriten during upgrades.

Backup and Restore concepts, issues and other information

The sme backup & restore concept is that only data (users & ibays) and configuration (including all mysql dbs and custom templates) is backed up & restored. All contribs (ie installed as rpms) are not backed up and normal templates (which are installed by the system or add on contribs) are not backed up.

A restore is done to a fresh installation of sme server, and then contribs are reinstalled. As configuration data is restored, you should not need to setup those reinstalled contribs again.

If you use any add on contrib for backup purposes eg Affa or Dar2 or whatever, then after doing a fresh reinstall of the sme OS, the first thing you do is reinstall the backup contrib and do some basic configuration manually. Then you would restore using that contrib, then you can reinstall all other contribs etc.

It's good admin practise to create an ibay specifically to house a copy of every rpm you install, so you can easily reinstall those from your backed up and restored copies, although with yum repos being available now, it's not so necessary to do this. It does provide a reminder of everything you have installed though, in case you forget.

The Affa contrib provides you with a report of missing rpms (if you enable that setting), which is the difference between the source server and the backup server, so you can easily see what needs reinstalling after a restore or Affa "rise", or install those on the Affa backup server in advance (if using a separate backup server).

Note that a tape backup backs up all file systems on the server, but only restores the "standard restore" files. See this list http://wiki.contribs.org/Backup_server_config#Standard_backup_.26_restore_inclusions

A full restore from a tape backup to a freshly installed sme OS, will cause all sorts of issues. The restored server will start to boot up but then grind to a halt during the startup/post configuration processes.

If using alternative full backup and full restore methods, problems will be experienced when attempting to restore rpms which have executables/binaries installed in the normal Linux file system locations, that's why they should be reinstalled. If you restore any of /lib, /bin etc onto a running SME server, you are almost certain to have problems.

Also some contribs will need to be updated if you restore to a newer version of the sme OS, so if you restore old contribs, then you will break your server, in some cases.

If you wish to backup "everything" (including installed rpms), then the standard sme backup methods (backup to desktop and backup with dar), and most of the available backup contribs eg DAR2, Affa, etc, do not backup "everything". You need to perform a bare metal or disk clone backup to achieve that. A contrib that does that is Mondo, but it appears to have not been updated to be compatible with sme7.x. Another way of easily doing this is to swap out a RAID1 disk, and plug in a clean (empty) disk. There will only be a few minutes downtime while the disk is swapped, as hot swap is not currently supported. After the clean disk is inserted, then use the admin console to resync the RAID1 array. Disk cloning software can also be used, but it must support RAID partitions and lvm volumes, and some cloning software does not. The Linux dd command will also copy every bit on a disk, to another mounted disk, but it will be slow and may take a long time (many many hours) for a disk with a lot of data. The server would ideally be disconnected from the local network and the Internet during this operation to prevent data changing on the server during the disk clone/backup process. Each of these methods has their own practical issues, choose the one that best suits your situation.

Add on scripts etc are best implemented via custom templates (which do get backed up), and any scripts can be put into /opt/xxx, and you then add /opt to your list of backup inclusions, or put them into an ibay if preferred, which does get backed up automatically.

The DAR2 contrib has a web interface that is configurable and allows you to create the disaster recovery backup (ie all data and configuration) required to rebuild a server, but you still need to reinstall add on contribs (rpms). It also allows allows selective backup jobs to be done, eg of certain ibays only, depending on your particular needs.

Reference links

http://wiki.contribs.org/UpgradeDisk

http://forums.contribs.org/index.php?topic=30745.0

http://forums.contribs.org/index.php?topic=39969.0

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