The YaST backup module enables you to create a backup of your system. The backup created by the module does not include the entire system. It only saves information about changed packages and copies of critical storage areas and configuration files.

Define the kind of data to save in the backup. By default, the backup includes information about any packages changed since the last installation. In addition, it may include data that does not belong to packages themselves, such as many of the configuration files in /etc or the directories under /home. Apart from that, the backup can include important storage areas on your hard disk that may be crucial when trying to restore a system, such as the partition table or the master boot record (MBR).

The restore module, shown in Figure 2.10, “Start Window of the Restore Module”, enables restoration of your system from a backup archive. Follow the instructions in YaST. Press ‘Next’ to proceed to the individual dialogs. First, specify where the archives are located (removable media, local hard disks, or network file systems). A description and the contents of the individual archives are displayed, enabling you to decide what to restore from the archives.

Additionally, there is a dialog for uninstalling packages that were added since the last backup and one for reinstalling packages that were deleted since the last backup. These two steps enable you to restore the exact system state at the time of the last backup.

	System Restoration
Because this module normally installs, replaces, or uninstalls many packages and files, use it only if you have experience with backups. Otherwise you may lose data.

Figure 2.10. Start Window of the Restore Module

Use this YaST module to create boot and rescue disks. These floppy disks are helpful if the boot configuration of your system is damaged. The rescue disk is especially necessary if the file system of the root partition is damaged.

Figure 2.11. Creating Boot and Rescue Disks

The following options are available:

To create one of these floppy disks, select the corresponding option and click ‘Next’. Insert a floppy disk when prompted. If you click ‘Next’ again, the floppy disk is created.

The logical volume manager (LVM) is a tool for custom partitioning of hard disks with logical drives. More information about LVM is available in Section 3.7, “LVM Configuration”.

With the expert dialog, shown in Figure 2.12, “The YaST Expert Partitioner”, manually modify the partitioning of one or several hard disks. Partitions can be added, deleted, and edited. Also access the soft RAID and LVM configuration from this YaST module.

	Warning
Although it is possible to modify the partitions in the installed system, this should be handled only by experts. Otherwise the risk of losing data is very high in case of a mistake. If you repartition a hard disk in use, reboot the system right afterwards. It is safer to use the rescue system than repartitioning the system while running.

Figure 2.12. The YaST Expert Partitioner

All existing or suggested partitions on all connected hard disks are displayed in the list of the expert dialog. Entire hard disks are listed as devices without numbers, such as /dev/hda or /dev/sda. Partitions are listed as parts of these devices, such as /dev/hda1 or /dev/sda1. The size, type, file system, and mount point of the hard disks and their partitions are also displayed. The mount point describes where the partition is mounted in the Linux file system tree.

If you run the expert dialog during installation, any free hard disk space is also listed and automatically selected. To provide more disk space to SUSE LINUX, free the needed space starting from the bottom toward the top of the list (starting from the last partition of a hard disk toward the first). For example, if you have three partitions, you cannot use the second exclusively for SUSE LINUX and retain the third and first for other operating systems.

    /dev/sda1    /data1    auto      noauto,user 0 0
    /dev/sda5    /data2    auto      noauto,user 0 0 
    /dev/sda6    /data3    auto      noauto,user 0 0
   

2.7.5.5. Partitioning and LVM

From the expert partitioner, access the LVM configuration with ‘LVM’ (see Section 3.7, “LVM Configuration”). However, if a working LVM configuration already exists on your system, it is automatically activated as soon as you enter the LVM configuration for the first time in a session. In this case, any disks containing a partition belonging to an activated volume group cannot be repartitioned because the Linux kernel cannot reread the modified partition table of a hard disk when any partition on this disk is in use. However, if you already have a functioning LVM configuration on your system, physical repartitioning should not be necessary. Instead, change the configuration of the logical volumes.

At the beginning of the physical volumes (PVs), information about the volume is written to the partition. In this way, a PV “knows” to which volume group it belongs. To reuse such a partiton for other non-LVM purposes, it is advisable to delete the beginning of this volume. For example, in the VG system and PV /dev/sda2, this can be done with the command dd if=/dev/zero of=/dev/sda2 bs=512 count=1.

	File System for Booting
The file system used for booting (the root file system or /boot) must not be stored on an LVM logical volume. Instead, store it on a normal physical partition.

The SCPM (system configuration profile management) module offers the possibility of creating, managing, and switching among system configurations. This is especially useful for mobile computers that are used in different locations (in different networks) and by different users. Nevertheless, this feature is useful even for stationary machines, because it enables the use of various hardware components or test configurations. For more information about SCPM basics and handling, refer to Chapter 15, System Configuration Profile Management.

SUSE LINUX can be operated in several runlevels. By default, the system boots to runlevel 5, which offers multiuser mode, network access, and the graphical user interface (X Window System). The other runlevels offer multiuser mode with network but without X (runlevel 3), multiuser mode without network (runlevel 2), single-user mode (runlevel 1 and S), system halt (runlevel 0), and system reboot (runlevel 6).

The various runlevels are useful if problems are encountered in connection with a particular service (X or network) in a higher runlevel. In this case, the system can be booted to a lower runlevel to repair the service. Many servers operate without a graphical user interface and must be booted in a runlevel without X, such as runlevel 3.

Usually you only need the standard runlevel (5). However, if the graphical user interface freezes at any time, you can restart the X Window system by switching to a text console with Ctrl-Alt-F1, logging in as root, and switching to runlevel 3 with the command init 3. This shuts down your X Window System, leaving you with a text console. To restart the graphical system, enter init 5.

For more information about the runlevels in SUSE LINUX and a description of the YaST runlevel editor, refer to Chapter 7, Booting and Configuring a Linux System.

The directory /etc/sysconfig contains the files with the most important settings for SUSE LINUX. The sysconfig editor displays all settings in a well-arranged form. The values can be modified and saved to the individual configuration files. Generally, manual editing is not necessary, because the files are automatically adapted when a package is installed or a service is configured. More information about /etc/sysconfig and the YaST sysconfig editor is available in Chapter 7, Booting and Configuring a Linux System.

The time zone was already set during the installation, but you can make changes here. Click your country or region in the list and select ‘Local time’ or ‘UTC’ (Coordinated Universal Time). ‘UTC’ is often used in Linux systems. Machines with additional operating systems, such as Microsoft Windows, mostly use local time.

Here, select the language for your Linux system. The language selected in YaST applies to the entire system, including YaST and the desktop environment.