Disaster Recovery mit der Sysresccd
Who of us doesn't know the problem: Our computer does not do what we want him to do and no way seem to outrun a complete re-installation.Be it a new virus or a hardware failure: Wouldn't it be nicer to save oneselfes the annoying re-installation of Linux or Windows?
Everyone of us who owns a server would be pleased, but also for desktop systems this kind of backup is quite interesting.
After installing and configuring the system once it can be saved as image without any problems.
It even doesn't matter where it shall be saved: another computer, harddisk or CD/DVD...
And that without spending a single euro for software!
Contents
1. What is Sysresccd
2. backup media
3. Partimage
4. backup/restore partition table
5. backup/restore boot sector
6. Nice to know / Example
1. what is Sysresccd
The Sysresccd is the ultimate collection of tools for backing up and restoring harddisk partitions and more.
Nearly no which stays ungranted.
- qtparted (Partition Magic Clone)
- partimage (Backup Software)
- CD/DVD creator
- Clam AntiVirus
- Chrootkits
- Webbrowser
- and, and, and ...
- ... more information about the tools can be found at
www.sysresccd.org
2. backup media
As Sysresccd is a Linux run from CD a device or network ressource to be used as backup storage has to be mounted.
You have the following possibilities:
- CD/DVD
- Harddisk
- external USB Harddisk
- NFS Share
- SMB Share
Attention: Never use /mnt as mount point! This is used by the system, too!
There is no problem crating new directories below /mnt so you could mount your destination device to /mnt/backup for example.
3. Partimage
"Partimage" can be used to back up your partitions.
Partimage works like the "dd"tool but has the advantage to save only used blocks.
So the created image is as small as possible.
The tool is run by executing
>> partimage
The user interface is quite easy and well explained.
In the first step the partitions to be backed up as well as the destination imagefile are chosen.
Dependingon the chosen action the image file is created/written or read and written to the chosen partition.
In the second step you can enable copression or set a split-size for the image (e.g. to bring it on multiple CDs but save it on harddisk in chunks to 700MB each first).
4. backup/restore partition table
To restore a crashed system you also need to back up the partition tabvle.
The partitions backed up using "partimage" do contain the file systgems but no information about the partition table.
>> sfdisk -d /dev/hda > part.tableRestoring the partition table from file can be done executing:
>> sfdisk /dev/hda < part.table
5. backup/restore boot sector
Most OSes (Linux/Windows) save their bootloader to the boot sector so this one should be backed up, too.
How this is done we will see here.
The boot sector are the first 512 byte on a harddisk.
To save those bytes we use the tool "dd".
>> dd if=/dev/hda of=/mnt/backup/hda.mbr bs=512 count=1This command writes the data from if(Inputfile) to of(Outputfile) using a bs(Blocksize) of 512 Byte. This will be done exactly one time.
Restoring the boot sector is as easy as backing it up, just swap input- and output file.
>> dd if=/mnt/backup/hda.mbr of=/dev/hda bs=512 count=1
6. Nice to know / Example
Some things to remark when using sysreccd:
- backing up NTFS partitions partimage gives the warning thatr NTFS support is only experimental, yet.
If the file system isn't that fragmented this should work nevertheless. As for me I never had any probles backing up NTFS partitions, yet. - if backing up via network the portmapper should be run befor doing so
Example for backing up via NFS Shares
A typical example for backing up a partition via NFS could look like that:
- cd booten
- configure network
>> ifconfig eth0 10.0.0.5 netmask 255.255.255.0 up
- start portmapper
>> /etc/init.d/portmap start
- vcreate mountpoint
>> mkdir /mnt/backup
- mount network ressource
>> mount 10.0.0.8:/images /mnt/backup
- backup/restore partition table
- backup/restore boot sector
- start partimage
If you still have quetions feel free to contact the author or use our forum.
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