Archive:SEP Sesam Server Linux BSR Restore EN

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BSR Disaster Restore (Self restore of a SEP sesam server using a LINUX BSR CD)

Introduction

The following example describes the self restore of a Linux system. In the case of a loss of the entire SEP sesam server data a restore with the Linux BSR CD is possible given that the necessary prerequisites are available and the preliminary work was done.

In this example we assume that a self backup of the SEP sesam server (SLEES10 SP2, 32 Bit) on tape exists. The drive of the SEP sesam server is broken and the system is supposed to be restored.

The restore is done on identical hardware. A restore on new or changed hardware is currently not supported i.e. can only be done with lots of additional work and expense.

Attention

outdated - Disaster Recovery for Linux 3.0 en should be used instead

Prerequisites

  • The system has to be backed up with three separate tasks. One task with the type "path" "full/copy" with the source "disk_info", a second task with the task "path" "full/copy" with the source "all" and a third task which is the predefined SEP sesam backup as a "full/copy" saveset. For this third task it is important to check if the path <SESAM-ROOT>/var/lis is included in the task.
  • SEP Sesam BSR ISO Image (bdr_<architecture.iso) burned on CD or bootable from the network.
  • Experience with the SEP sesam "sm_recover" interface and using SEP sesam in general.
  • Experience with the Linux Shell.

Course of Action

Here is the order of things to do for the restore:

  • Boot from the SEP sesam BSR Live CD
  • Start the SEP sesam server (Button on the desktop) from the Live CD
  • Check the SEP sesam configuration (Drive or Disk-Storage has to be known by the virtual SEP sesam instance) / start a root shell
  • Restore the "disk_info" information in the Live-CD ramdisk
  • Start the "disk_info" restore on the command line
  • Restore the "all" backup with sm_recover to /mnt/disk
  • Install the GRUB boot loader
  • Reboot the system.

Boot the SEP sesam BSR Live CD

After inserting the CD the "boot:" prompt appears. Just press Enter here. After booting the graphical GNOME interface is started. Then the Xnetconfigurator, which is necessary for the configuration of the network, starts as well. This enables you to configure available network cards which is not necessary in the current example but it is generally a good thing to have:

Boot Prompt:



Start the SEP sesam Server from the Live CD

The installation of the SEP sesam server is done with the desktop icon "SEP sesam server setup":


After executing the setup automatically starts the graphical user interface.


Check the SEP sesam Configuration / Start a Root Shell

In order to run a restore it is necessary for the SEP sesam server to have access to the tape device or disk that is connected to the system. Usually, all available tape devices are detected by the SEP sesam server automatically. If this is not the case all necessary steps have to be taken to get access to the tape device.

Checking the configuration is done in two steps:

  • Check with the GUI
  • Read a tape label from the drive (the tape has to be in the drive)

In this example a USB AIT Tape Device, which is connected directly to the mainboard on the SEP sesam server, is used:

GUI check:


If the drive is configured correctly and all drive structures were created a root shell has to be started with the icon "Root Shell". The SEP sesam GUI can either be left open or closed at this point. It is not needed for any of the remaining steps.


The SEP sesam profile is sourced automatically in the root shell. Now, using the tool "sm_sms_interface", check if the label of the tape can be read with the following command:


If the label (in this example "sesam-backup00001") can be read successfully, the actual restore can be started. If not, check the drive configuration.

Restore of the "disk_info" Information in the Live-CD Ramdisk

The "disk_info" information is first restored over the sm_recover interface and then executed manually. The restore is done as follows.

The tool "sm_recover" is started in the shell. This tool requires some information.

First it asks what device is supposed to be used:



Now the SEP sesam server demands a locking mode:


Afterwards, you're asked if the information about the individual savesets and segment markers of the savesets is available or if it has to search all the savesets on the tape itself. This information can be taken from the disaster emails of the SEP sesam server. Alternatively the sm_recover interface lists all savesets on the tape.

This process may take some time. In our example we're having the tape searched and three backups are found: 2x disk_info and one "All" backup. In case you have all the information at hand you can also make the selection yourself and enter the according tape, saveset, and segment number information.


Now, the according saveset for a restore can be selected. In this case the newest "disk_info" backup is selected (Saveset "2"):


After confirming the questions whether a restore or just a list is to be done, if original files may be overwritten and which restore target is to be used (in this case /tmp/), the restore is executed:


The "disk_info" backup is restored to /tmp/var/opt/sesam/var/work/disk_info/ in the Ramdisk:


Start the "disk_info" Restore on the Command Line

In the next step the "disk_info" information is written back to the hard disk. Here the SEP tool "sbc_disk_info_restore" is employed. The first transfer parameter this tool uses is the path of the "disk_info" information, the second one is the keyword "auto":


The disk in the system has to at least be the size of the old disk or larger. After creating the partitions and logical volumes they are embedded in the ramdisk into "/mnt/disk".


Next, you have to check if all partitions were created and embedded (using e.g. "df"):


Restore the "all" backup with sm_recover to /mnt/disk

Now the "all" backup set on the tape has to be restored. It is important here to restore to /mnt/disk, i.e. the actual partitioned disks and not the ramdisk.

This restore is done with sm_recover again:


Next, the according "All" saveset has to be selected:


And the according restore target, and accordingly if data should be copied:


After this the restore is started:


Once the restore has finished successfully it is time to write the GRUB bootloader information back into the master boot record.

Installation of the GRUB Bootloader

Now, using the tool "grub-install", the bootloader can be rewritten to make the system bootable:


In the following example the script "grub-install" requires two transfer parameters:

  • where is the installed system
  • for which hard drive do you want to install the bootloader

In this example we assume that the bootloader is supposed to be installed into the first hard drive (hd0). You can find out which hard drives are available in the system with the file:

/mnt/disk/boot/grub/device.map

Once the installation of the GRUB bootloader is confirmed with the message "Installation finished, no Errors Reported" (the error "unary operator expected" can be ignored), the Live-CD system can be restarted with "reboot". The original system should boot now with the next system start.

Troubleshooting