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How to configure multiple local system backup disks

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This how-to will describe the steps necessary to utilize multiple Local System Backup Disks. These disks may then be used as part of a backup rotation scheme.

A Local System Backup Disk (often referred to as SBDIR) is a dedicated disk(s) specifically configured to allow hosts to write system backups to local disk. Users may then perform system recovery from these disks.

SBAdmin currently supports the configuration of a single SBDIR per host or client. We understand that these disks are often external and removable (ie. USB drive), and that users may want to use more than one SBDIR as part of a backup rotation scheme. This how-to will describe the steps to support multiple SBDIR's on a Linux system using the SBAdmin GUI interface.

Prerequisites

  • SBAdmin Network Edition with a configured Linux client
  • 2 or more external disks (ie. USB drives)
  • General understanding of Linux device naming
  • General understanding of mounting and unmounting devices on Linux
  • Ability to edit files in Linux

Configuring Multiple Local System Backup Disks

This how-to will detail the steps using the SBAdmin GUI. However, the steps will be the same if you are using the SBAdmin Web Interface.

Each SBDIR must be configured independently. Therefore, you should only have one of the disks attached to the client system at a time. 

Configure first Local System Backup Disk

With the first disk you wish to configure as a SBDIR device attached to the client, select Configure->Clients from the SBAdmin GUI.



Enter the client hostname into the Client Hostname/IP entry field ("smee" is the client we will use in this how-to).

In the section Local System Backup Options, select the Disk tab. Select from the Disk(s) for Local System Backups drop-down list the disk that you wish to configure ("sdb" is the disk we wish to configure in this how-to).
 
The disks displayed when selecting the drop-down are only those that are currently unused and undefined to the system. Some Linux distributions have subsystems (ie. hald, udev) that will automount devices that have filesystems on them. Therefore, if the disk or a partition on the disk is currently mounted it will not be displayed. You should unmount all devices related to this disk.

# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/hdb2              3745480   2195996   1356156  62% /
/dev/hdb1               505604     43630    435870  10% /boot
tmpfs                  1021236         0   1021236   0% /dev/shm
/dev/sdb1              7810152         4   7810148   1% /media/disk

# umount /dev/sdb1

Also, if the disk or a partition on the disk is defined in /etc/fstab it will not be displayed from the drop-down. You should remove all entries related to this disk from /etc/fstab.

# cat /etc/fstab
/dev/hdb2      /               ext3    defaults        1 1
/dev/hdb1      /boot           ext3    defaults        1 2
devpts         /dev/pts        devpts  gid=5,mode=620  0 0
tmpfs          /dev/shm        tmpfs   defaults        0 0
proc           /proc           proc    defaults        0 0
sysfs          /sys            sysfs   defaults        0 0
/dev/hdb3      swap            swap    defaults        0 0
/dev/sdb1      /media/disk     ext3    defaults        1 1  # REMOVE

After selecting the disk, the Filesystem Mount Point (directory) field will default to
/backups/local/system
as the directory that backups will be written to. You may change this directory, but for this how-to we will leave it as the default.

The Configure Disk(s) Using option will default to LVM. While it is possible to configure multiple SBDIR's using LVM, it is easier to manage these disks when using the Partition option. Select the Partition option.

The window should look similar to the following:



At this point you are ready to save the client configuration which will also configure the SBDIR on the client. Select Save. You will be prompted to confirm that you wish to overwrite the selected system backup disk.
 
IMPORTANT
While SBAdmin attempts to prevent you from selecting a disk that may have data on it, you must be sure you have selected the correct disk. All data on the selected SBDIR will be destroyed when it is configured.

A Configuring System Backup Disk status window will appear detailing the configuration process. Note that one of the steps during this process is to make the selected disk bootable. If your system firmware/BIOS supports booting from this device then you may use this disk as your SBAdmin boot media for disaster recovery purposes.

Configuration of the first SBDIR is complete and you may close the status window.

Remove configuration of first Local System Backup Disk

Because you are configuring multiple SBDIR's, the configuration files related to the first disk must be removed but the actual configuration on the disk must remain. For that reason, there are some manual steps that need to be taken.

Before physically removing the first SBDIR you should properly unmount it.

# umount /backups/local/system

Now you may remove the first SBDIR from the client system.

Next, you need to remove the SBDIR configuration of the client from the SBAdmin Administrator. To do so, you must remove a file on the Administrator system. The file to remove will depend on which group the client resides in and the directory used to store SBAdmin configuration files. Client "smee" resides in the "main" group and the data directory on the Administrator is /storix (the default). Therefore, the file to remove is /storix/main/data/clients/smee:SBDIR

On the Administrator system:

# rm /storix/main/data/clients/smee:SBDIR

Next, you need to remove the SBDIR configuration on the client system. To do so, you must remove a SBAdmin configuration file and a line from the /etc/fstab file. The file to remove will depend on your Storix data directory on the client. The storix data directory on client "smee" is /storix (the default). Therefore, the file to remove is /storix/config/vdev:SBDIR.

On the client system:

# rm /storix/config/vdev:SBDIR

You need to remove the line from /etc/fstab that defines the mount point for the first SBDIR. In our case it is the line defining /dev/sdb2 to be mounted on /backups/local/system.

# cat /etc/fstab
/dev/hdb2      /               ext3    defaults        1 1
/dev/hdb1      /boot           ext3    defaults        1 2
devpts         /dev/pts        devpts  gid=5,mode=620  0 0
tmpfs          /dev/shm        tmpfs   defaults        0 0
proc           /proc           proc    defaults        0 0
sysfs          /sys            sysfs   defaults        0 0
/dev/hdb3      swap            swap    defaults        0 0
/dev/sdb2      /backups/local/system  ext2  noauto     0 0  # REMOVE

Configure second Local System Backup Disk

Attach the second disk you wish to configure as a SBDIR to the client and repeat the steps above for configuring the first SBDIR. Do not remove the configuration from the Administrator or the client unless you will be configuring a third disk.

You now have multiple SBDIR's configured and may configure system backup jobs to write to them.

Rotating the Local System Backup Disks

The assumption is that you will be rotating these SBDIR's as part of a backup rotation scheme. The steps to properly remove one SBDIR from the system and attach the other are simple. Note that if you configured the SBDIR's using the LVM option the steps are different.
 
1. Unmount the currently attached SBDIR

# umount /backups/local/system

2. Remove attached SBDIR
3. Attach next SBDIR
4. Mount next SBDIR

# mount /backups/local/system


Conclusion

The ability to write backups to local disk provides many advantages: performance, less network traffic, portability, etc. For these reasons, Storix has developed the Local System Backup Disk (SBDIR) feature withing SBAdmin. While the SBAdmin interface will not support managing multiple SBDIR's, it is easy to configure and use multiple SBDIR's as part of your backup rotation scheme.

References