Restoring a Suse Linux Enterprise Server 9 64 Bit on Dissimilar Hardware with CBMR for Linux 1.02

Transcription

1 Cristie Bare Machine Recovery Restoring a Suse Linux Enterprise Server 9 64 Bit on Dissimilar Hardware with CBMR for Linux 1.02 This documentation shows how to restore or migrate a Linux system on dissimilar hardware. This document describes the restoring process for 64 Bit Linux Systems. When trying to restore a SLES9 from i.e. a HP-Netraid Server with a built-in Megaraid controller into VMware with a built-in Buslogic controller, without changing the system, you ll typically get the following output: As a result the boot process will be stopped without the ability to recover the system. To avoid this, the following changes have to be made before booting the system. 1. Requirements The hard disks should have the same size or should be bigger than the ones in the source server you wish to recover. The new system should be supported by the current Linux Version. The device driver for the new RAID-/Storage controller should use the same device nodes like the old one (like /dev/sda, or /dev/cciss/c0d0). The kernel drivers for the new RAID-/Storage controller should be found in the filesystem and should be backed up with CBMR. The complete backup of the system data should have been done.

2 2. Step by Step tutorial 2.1 Boot up the recovery machine with the CBMR bootmedia. Load all needed drivers to access the harddisks and the recovery media (NIC driver). You should write down the drivers you need to access the harddisk in the new server as you will need this information later. In our example we need the BusLogic driver to access the harddisk You can also list all loaded modules in the CBMR Recovery GUI 2.2 Do an Automatic Recovery to restore the system on the new hardware. Partitions will be created and formatted, data will be restored and at the end the bootsector will be written. After this, the Main Menu will appear. 2.3 We will now have to modify the system and rebuild the initrd with the new storage controller modules. But first we have to write down all mountpoints which are mounted at /mnt/slash*

3 2.4 Select Advanced Options Linux Bash Shell 2.5 In the Linux Bash shell enter following command to find out which volumes are mounted : mount grep slash Write down the mountpoints - they are needed to mount the disk within the 64-bit recovery CD. 2.6 Please exit and Restart your system with a 64-bit Rescue CD like the first Media from SLES9 64bit or SLES10 64bit. 2.7 Boot up a rescue shell and make sure that all needed kernel modules for accessing the harddisks are loaded. fdisk -l will show all available disks and partitions. If your disk is missing, you have to load the kernel module which you figured out in 2.1 manually modprobe buslogic

4 2.8 Create a directory called /mnt/slash and mount all needed volumes: 2.9 Type the following commands into the command shell: Now we changed into the restored system which is mounted at /mnt/slash Here you can see that the /etc is the restored directory with the right data - SLES Try to find out if the same driver that you have written down in 2.1, is also available on this system by typing the following command: This search is case sensitive - if you don t find your driver, try this: Now we know that our SLES9 comes with a driver for the current storage controller. That s the driver we have to load during starting of Linux Edit following file : (You can also use your favorite editor like emac or ed) We search for the following line : INITRD_MODULES= xxxxxxx At line 10 we found out that megaraid and reiserfs are kernel modules which are loaded during the bootup process from the kernel.

5 megaraid is the driver for our HP-Netraid Controller from our origin system. As we don t need this driver anymore we have to add the BusLogic kernel module for our destination system. So we have to edit the line and replace megaraid with BusLogic. (Attention - case sensitive) Save the file and quit to bash We have now edited the configuration file for building an initial ramdisk which is loaded from the kernel during the boot-up process. Now we have to build this with this command: mkinitrd will now build our initial ramdisk The print above shows that the new Kernel Module BusLogic.ko is included That s it. Type exit to leave the virtual root and return to SLES 9/10 64bit Recovery Console. Umount all your filesystems mounted at /mnt/slash and restart the system. The system will now boot up with your restored SLES9 and the needed storage controller Our system boots up, loads the BusLogic.ko kernel module and complains about missing network cards and changed graphics card. We can now change the drivers for the new hardware manually or with the Suse configuration tool called yast.