6.4. Problems After Installation

6.4. Problems After Installation

6.4.1. Trouble With the Graphical GRUB Screen on an x86-based System?

If you are experiencing problems with GRUB, you may need to disable the graphical boot screen. To do this, become the root user and edit the /boot/grub/grub.conf file.

Within the grub.conf file, comment out the line which begins with splashimage by inserting the # character at the beginning of the line.

Press Enter to exit the editing mode.

Once the boot loader screen has returned, type b to boot the system.

Once you reboot, the grub.conf file is reread and any changes you have made take effect.

You may re-enable the graphical boot screen by uncommenting (or adding) the above line back into the grub.conf file.

6.4.2. Booting into a Graphical Environment

If you have installed the X Window System but are not seeing a graphical desktop environment once you log into your Red Hat Enterprise Linux system, you can start the X Window System graphical interface using the command startx.

Once you enter this command and press Enter, the graphical desktop environment is displayed.

Note, however, that this is just a one-time fix and does not change the log in process for future log ins.

To set up your system so that you can log in at a graphical login screen, you must edit one file, /etc/inittab, by changing just one number in the runlevel section. When you are finished, reboot the computer. The next time you log in, you are presented with a graphical login prompt.

Open a shell prompt. If you are in your user account, become root by typing the su command.

Now, type gedit /etc/inittab to edit the file with gedit. The file /etc/inittab opens. Within the first screen, a section of the file which looks like the following appears:

          # Default runlevel. The runlevels used by RHS are: # 0 - halt (Do NOT set initdefault to this) # 1 - Single user mode # 2 - Multiuser, without NFS (The same as 3, if you do not have networking) # 3 - Full multiuser mode # 4 - unused # 5 - X11 # 6 - reboot (Do NOT set initdefault to this) # id:3:initdefault:
        

To change from a console to a graphical login, you should change the number in the line id:3:initdefault: from a 3 to a 5.

Warning

Change only the number of the default runlevel from 3 to 5.

Your changed line should look like the following:

	 id:5:initdefault: 

When you are satisfied with your change, save and exit the file using the Ctrl-Q keys. A window appears and asks if you would like to save the changes. Click Save.

The next time you log in after rebooting your system, you are presented with a graphical login prompt.

6.4.3. Problems with the X Window System (GUI)

If you are having trouble getting X (the X Window System) to start, you may not have installed it during your installation.

If you want X, you can either install the packages from the Red Hat Enterprise Linux CD-ROMs or perform an upgrade.

If you elect to upgrade, select the X Window System packages, and choose GNOME, KDE, or both, during the upgrade package selection process.

6.4.4. Problems with the X Server Crashing and Non-Root Users

If you are having trouble with the X server crashing when anyone other than root logs in, you may have a full file system (or, a lack of available hard drive space).

To verify that this is the problem you are experiencing, run the following command:

df -h

The df command should help you diagnose which partition is full. For additional information about df and an explanation of the options available (such as the -h option used in this example), refer to the df man page by typing man df at a shell prompt.

A key indicator is 100% full or a percentage above 90% or 95% on a partition. The /home/ and /tmp/ partitions can sometimes fill up quickly with user files. You can make some room on that partition by removing old files. After you free up some disk space, try running X as the user that was unsuccessful before.

6.4.5. Problems When You Try to Log In

If you did not create a user account in the Setup Agent, log in as root and use the password you assigned to root.

If you cannot remember your root password, boot your system as linux single.

Itanium users must enter boot commands with elilo followed by the boot command.

If you are using an x86-based system and GRUB is your installed boot loader, type e for edit when the GRUB boot screen has loaded. You are presented with a list of items in the configuration file for the boot label you have selected.

Choose the line that starts with kernel and type e to edit this boot entry.

At the end of the kernel line, add:

	single

Press Enter to exit edit mode.

Once the boot loader screen has returned, type b to boot the system.

Once you have booted into single user mode and have access to the # prompt, you must type passwd root, which allows you to enter a new password for root. At this point you can type shutdown -r now to reboot the system with the new root password.

If you cannot remember your user account password, you must become root. To become root, type su - and enter your root password when prompted. Then, type passwd <username>. This allows you to enter a new password for the specified user account.

If the graphical login screen does not appear, check your hardware for compatibility issues. The Hardware Compatibility List can be found at:

	http://hardware.redhat.com/hcl/

6.4.6. Is Your RAM Not Being Recognized?

Sometimes, the kernel does not recognize all of your memory (RAM). You can check this with the cat /proc/meminfo command.

Verify that the displayed quantity is the same as the known amount of RAM in your system. If they are not equal, add the following line to the /boot/grub/grub.conf:

          
            mem=xxM
          
        

Replace xx with the amount of RAM you have in megabytes.

In /boot/grub/grub.conf, the above example would look similar to the following:

          # NOTICE: You have a /boot partition. This means that # all kernel paths are relative to /boot/ default=0 timeout=30 splashimage=(hd0,0)/grub/splash.xpm.gz title Red Hat Enterprise Linux (2.6.9-5.EL) root (hd0,0) kernel /vmlinuz-2.6.9-5.EL ro root=/dev/hda3 mem=128M
        

Once you reboot, the changes made to grub.conf are reflected on your system.

Once you have loaded the GRUB boot screen, type e for edit. You are presented with a list of items in the configuration file for the boot label you have selected.

Choose the line that starts with kernel and type e to edit this boot entry.

At the end of the kernel line, add

          
            mem=xxM
          
        

where xx equals the amount of RAM in your system.

Press Enter to exit edit mode.

Once the boot loader screen has returned, type b to boot the system.

Itanium users must enter boot commands with elilo followed by the boot command.

Remember to replace xx with the amount of RAM in your system. Press Enter to boot.

6.4.7. Your Printer Does Not Work

If you are not sure how to set up your printer or are having trouble getting it to work properly, try using the Printer Configuration Tool.

Type the system-config-printer command at a shell prompt to launch the Printer Configuration Tool. If you are not root, it prompts you for the root password to continue.

6.4.8. Problems with Sound Configuration

If, for some reason, you do not hear sound and know that you do have a sound card installed, you can run the Sound Card Configuration Tool (system-config-soundcard) utility.

To use the Sound Card Configuration Tool, choose Main Menu => System => Administration => Soundcard Detection in GNOME, or Main Menu => Administration => Soundcard Detection in KDE. A small text box pops up prompting you for your root password.

You can also type the system-config-soundcard command at a shell prompt to launch the Sound Card Configuration Tool. If you are not root, it prompts you for the root password to continue.

If the Sound Card Configuration Tool does not work (if the sample does not play and you still do not have audio sounds), it is likely that your sound card is not yet supported in Red Hat Enterprise Linux.

6.4.9. Apache-based httpd service/Sendmail Hangs During Startup

If you are having trouble with the Apache-based httpd service or Sendmail hanging at startup, make sure the following line is in the /etc/hosts file:

127.0.0.1  localhost.localdomain  localhost

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