SystemRescueCd and Partimage

System Rescue CD is a live distribution with several tools for repairing file systems. It can be used through a CD-Rom, a pen-drive, or a floppy. In the case of a pendrive, boot from a USB device must be on in the BIOS. Furthermore, in some mobos, it is necessary to access the BIOS with the pendrive plugged in, select the tab Boot -> Hard Disk Drives, and set the pendrive to be the 1st drive. In any case, the pendrive must be made bootable.

During the boot, SystemRescueCd detects the hardware and allows the choice of the keyboard type. If the computer is on a network, just type
net-setup eth0 from the command-line, and configure the network.

For creating partitions, run_qtparted used to start QtParted. Newer versions, however, are shipping gparted, instead. In this case, xinit has to be run before calling gparted, because it only works in graphical mode. It is possible then to delete, create, or format partitions. It is never too much to remind people to backup important data before any attempt to modify partitions. There is always the risk of messing the partition table, although, in general, this does not happen.

Partimage can be used for backing up a partition, and its usage is straightforward. Just highlight the partition to be saved, choose a name for its backup, and optionally another machine on the network, running a partimage server, to receive the image. In the server, the file /etc/sysconfig/partimaged should contain options like this:

OPTIONS="--port=4025 --dest /your_image_dir/images"

The client must always be run as root, and it can optionally use a password for accessing the server. However, the client must have been compiled with "login" enabled, in this case. In fact, the client compilation options, and the server options, must match, e.g., ssl and login. Otherwise, a "version mismatch" error occurs. Should your client use "login", the users allowed to connect to the server must be listed in the file /etc/partimaged/partimagedusers, one per line. If, besides using login, pam support is also enabled, the authentication is done based on a db4 database created by the script /usr/share/partimaged/partimaged-passwd. The database entries are pairs of (user,password). Please, read man partimaged-passwd for getting all the options on how to add/delete users from the database.

For using the ssl capability, the certificates have to be created by running /usr/share/partimaged/create_certificates.sh. The file /etc/partimaged/partimage-certs.cnf can be customized, in order to change information, such as, Country, State and Location. Clients supplied with SystemRescueCd, version 1.3.1 or greater, ARE compiled with ssl and login enabled. Therefore, the partimage package was created with the same options also enabled. Please, note that, for disabling ssl in the server, it is enough to add the option --nossl to its configuration file, and restart the server. To check which compilation options have been chosen, just type partimaged -i.

Another point is that the client and server architectures must be the same. Therefore, if you use a CD with a 32 bit client, the server must be a 32 bit version too, even if it is running on a 64 bit platform.

The backup files should be named using mnemonics easy to remember, such as, boot-hostname-Fx or root-hostname-Fx. There is also an option to break the image in parts, so they fit on a CD. Generally, 690MB is a good choice, which will produce root-hostname-Fx.000, root-hostname-Fx.001, etc... If you do not want to save the image on another computer, then just mount another partition on the same computer to receive the image.

To restore a backup, just do the reverse, highlight the partition to be restored, and type the name of the first file of the backup: root-hostname-Fx.000.

Remember that the size of the partition to be restored must be greater or equal than the size of the saved partition. If it is greater, then the corresponding file system should be enlarged to occupy all of the available space. For an ext3 file system, use:

e2fsck -f /dev/sdan
resize2fs -f /dev/sdan

The enlargement of the size of the file system can be done at any time later, and it is not mandatory (but the excess is lost, otherwise).