Once you have installed and switched to LDAP authentication the system may seem to hang on boot-up when the messagebus daemon tries to initialize. Though eventually after a very long time-out it will continue the boot process. This is related to authentication being required while messagebus daemon starts prior to the LDAP daemon. A quick work-around to solve this issue is to change the boot sequence, the messagebus daemon has to be started after the LDAP daemon. To accomplish this type:

mv /etc/rc.d/rc3.d/S22messagebus /etc/rc.d/rc3.d/S28messagebus
mv /etc/rc.d/rc5.d/S22messagebus /etc/rc.d/rc5.d/S28messagebus
chkconfig --level 4 messagebus off

NFS is a widely used network filesystem protocol allowing the client to access files over the network as if they are locally stored. To avoid the NFS share to become a SPOF (Single Point Of Failure) you can create a high available NFS share using DRBD and Heartbeat.

First we install the necessary packages on two servers:

Although very rare Linux might get stuck as well and won't respond to keystrokes or other user input. In the worst case there is a kernel crash, sometimes with a kernel crash dump on the console, probably caused by an unstable driver or hardware problems.
If you are lucky the system stucks but you are able to login from a remote machine by ssh. You can kill the process kill -9 ... or reboot the system shutdown -r now. Most of the times a jam is caused by one or more processes consuming too many recourses. Symtomps are extreme high CPU usage, high load, high memory usage, a high queue of waiting processes ect. If there are no resources left the kernel might still be running but the system doesn't responed to keystrokes, CTRL+ALT+DEL won't help and login from an other system with ssh is also impossible, as there are no resources left to start a new shell.

An easy way to run your Linux X applications on your Windows desktop is to use the SSH X11Forwarding capability. If you enable X11Forwarding on the SSH server you will be able to display GUI applications, running on the server, on your Windows desktop. Edit /etc/ssh/sshd_config and change the line X11Forwarding no into:

X11Forwarding yes

On your Windows desktop you should have an ssh-client and a X-server. A good choice to install on your Windows machine would be CYGWIN. (http://www.cygwin.com) Download setup.exe and follow the setup instructions. To be able to use X11 over SSH you need to select openssh from the NET group, and xorg-server, xterm and X-start-menu-icons from the X11 group. After finishing the installation start the X-server on your windows machine. In the CYGWIN shell type:

export DISPLAY=:0.0

followed by

ssh -X yourusername @linuxserver.yourdomain.com

Now you can display your X applications on your Windows desktop. For example type

xclock&

and the clock will be displayed on your desktop.