2.8. System

[Tip]S/390, zSeries: Continuing

For IBM S/390 and zSeries, continue with Section 2.8.5. “LVM”.

2.8.1. Backup Copy of the System Areas

The YaST backup module enables you to create a backup of your system. The backup created by the module does not comprise the entire system, but 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).

2.8.2. Restoring the System

The restore module, shown in Figure 2.19. “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 are two dialogs for uninstalling packages that were added since the last backup and for the reinstallation of 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.

[Warning]System Restoration

As this module normally installs, replaces, or uninstalls many packages and files, use it only if you have experience with backups, as otherwise you may lose data.

Figure 2.19. Start Window of the Restore Module

Start Window of the Restore Module

2.8.3. Creating a Boot, Rescue, or Module Disk

[Tip]S/390, zSeries: System Repair

The procedure described below does not apply to IBM S/390 and zSeries platforms. Refer to Section 6.5. “S/390, zSeries: Using initrd as a Rescue System” for details on the rescue procedure for these platforms.

Use this YaST module to create boot disks, rescue disks, and module 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. In this case, you might also need the module disk with various drivers to be able to access the system (e.g., to access a RAID system).

Figure 2.20. Creating a Boot, Rescue, or Module Disk

Creating a Boot, Rescue, or Module Disk

The following options are available:

Standard Boot Disk

Use this option to create a standard boot disk with which to boot an installed system. This disk is also needed for starting the rescue system.

Rescue Disk

This disk contains a special environment that allows you to perform maintenance tasks in your installed system, such as checking and repairing the file system and updating the boot loader.

To start the rescue system, boot with the standard boot disk then select Manual Installation+Start Installation or System+Rescue System. You will then be prompted to insert the rescue disk. If your system was configured to use special drivers (such as RAID or USB), you might need to load the respective modules from a module disk.

Module Disks

Module disks contain additional system drivers. The standard kernel only supports IDE drives. If the drives in your system are connected to special controllers (such as SCSI), load the needed drivers from a module disk. If you select this option and click Next, you will be taken to a dialog for creating various module disks.

The following module disks are available:

USB Modules

This floppy disk contains the USB modules you might need if USB drives are connected.

IDE, RAID, and SCSI Modules

As the standard kernel only supports normal IDE drives, you will need this module disk if you use special IDE controllers. Furthermore, all RAID and SCSI modules are provided on this disk.

Network Modules

If you need access to a network, load the suitable driver module for your network card from this floppy disk.

PCMCIA, CD-ROM (non-ATAPI), FireWire, and File Systems

This floppy disk contains all PCMCIA modules used especially for laptop computers. Furthermore, the modules for FireWire and some less common file systems are available here. Older CD-ROM drives that do not comply with the ATAPI standard can also be operated with drivers from this floppy disk.

To load drivers from a module disk to the rescue system, select Kernel Modules (hardware drivers) and the desired module category (SCSI, ethernet, etc.). You are prompted to insert the respective module disk and the contained modules are then listed. Select the desired module. Watch the system messages carefully: Loading module <modulename> failed indicates that the hardware could not be recognized by the module. Some older drivers require specific parameters to be able to address the hardware correctly. In this case, refer to the documentation of your hardware.

User-Defined Disk

Use this to write any existing floppy disk image from the hard disk to a floppy disk.

Download Disk Image

With this, enter a URL and authentication data to download a floppy disk image from the Internet.

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.

2.8.4. Boot Loader Configuration

[Tip]S/390, zSeries: YaST Boot Loader Configuration

Boot loader configuration through YaST is not supported on IBM S/390 and zSeries.

A detailed description of how to configure the boot loader with YaST is available in Section 8.6. “Configuring the Boot Loader with YaST”.

2.8.5. LVM

The Logical Volume Manager (LVM) is a tool for custom partitioning of hard disks into logical drives. Information about LVM is available in Section 3.10. “LVM Configuration”.

2.8.6. EVMS

The enterprise volume management system (EVMS) is, like LVM, a tool for custom partitioning and grouping of hard disks into virtual volumes. It is flexible, extensible, and can be tailored using a plug-in model to individual needs of various volume management systems.

EVMS is compatible with already existing memory and volume management systems, like DOS, Linux LVM, GPT (GUID Partition Table), S/390, Macintosh, and BSD partitions. More information is provided on http://evms.sourceforge.net/.

2.8.7. Partitioning

Although it is possible to modify the partitions in the installed system, this should be handled by experts who know exactly what they are doing, as otherwise the risk of losing data is very high. If you decide to use this tool, refer to the description in Section 1.7.4. “Partitioning” (the partitioning tool during the installation is the same as in the installed system).

2.8.8. Profile Manager (SCPM)

[Tip]S/390, zSeries: Profile Manager

This module is not relevant for SUSE LINUX Enterprise Server on IBM S/390 and zSeries.

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, as it enables the use of various hardware components or test configurations. For more information about SCPM basics and handling, refer to the respective sections in Chapter 16. Linux on Mobile Devices.

2.8.9. Runlevel Editor

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.

In a default installation, runlevel 5 is selected. To start a different runlevel when the system is booted, change the default runlevel here. With Runlevel properties, determine which services are started in which runlevel.

[Warning]Runlevel Configuration

Incorrect settings for system services and runlevels can render your system useless. To retain the operability of your system, consider the possible consequences before modifying any of these settings.

More information about runlevels in SUSE LINUX can be found in Chapter 11. The SUSE LINUX Boot Concept.

2.8.10. Sysconfig Editor

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, as the files are automatically adapted when a package is installed or a service is configured.

[Warning]System Configuration with /etc/sysconfig/

Do not edit the files in /etc/sysconfig if you do not know exactly what you are doing, as this could seriously inhibit the operability of your system.

More information about /etc/sysconfig/ can be found in Chapter 11. The SUSE LINUX Boot Concept.

2.8.11. Time Zone Selection

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 GMT (Greenwich Mean Time). GMT is often used in Linux systems. Machines with additional operating systems, such as Microsoft Windows, mostly use local time.

2.8.12. Language Selection

Here, select the language for your Linux system. The language can be changed at any time. The language selected in YaST applies to the entire system, including YaST and the desktop environment KDE.

2.8.13. Keyboard Layout Selection

[Tip]S/390, zSeries: Keyboard Layout

Because IBM S/390 and zSeries do not have a locally attached keyboard, this module has no relevance for these architectures.

[Important]Configuration of the Keyboard Layout

Only use this module if you work on a system without the X Window System and a graphical user interface. If you use a graphical system (such as KDE), set up the keyboard with the module Display and Input Devices. See Section 2.4.5. “Graphics Card and Monitor (SaX2)”.

The desired keyboard layout usually matches the selected language. Use the test field to see if special characters, such as the pipe symbol |, are displayed correctly.