If you like the way snapshots work for virtual machines, you'll love that same physical system functionality with Redo.
Now it’s time to return to the Home screen, where the real Redo action happens. Select Backup or Restore from the list of options to move to the next screen to choose between backup or restore for your system.
Select Backup to start the backup process for your system. Note: You have to step through this backup procedure at least once prior to experiencing any failures on your system so that you have a restore point from which to choose. See Figure 6.
Figure 6: Beginning the Backup Process.
The first step in the backup process is to select your source drive for backup as shown in Figure 7. This example shows a virtual machine disk image but it works similarly for physical systems. Choose the drive that you wish to use as your backup source from the dropdown list and click Next to continue.
Figure 7: Selecting the Backup Source Drive in the Backup Wizard.
Figure 8 demonstrates that you can select individual partitions from the drive you chose in Figure 7 above. It’s recommended that you select all partitions as backup sources. You can choose individual partitions to restore during that part of the process. Click Next to continue.
Figure 8: Selecting the Backup Source Partitions in the Backup Wizard.
Select your destination folder for the backup. Either type in the full path or click the Browse button to interactively choose a location as shown in Figure 9. The path shown in Figure 9 is a locally connected USB drive. Click Next to continue.
Figure 9: Selecting the Backup Destination Location.
Finish the backup wizard and the backup begins as shown in Figure 10. The progress indicator keeps on the backup status. For an 8GB disk, the process takes very little time. Performing this same process on a 500GB disk takes about 35 minutes backing up to a local USB drive.
Figure 10: Backup in Progress.
How much space do you need for a backup? The 8GB virtual disk backup consumed 1.34GB of disk space and the 500GB physical disk nibbled a bit more at just over 4GB. The compression ratios are impressive but your consumed space will depend on the type of data on your source disk and how full the disk is.
The restore process works like the backup procedure but in reverse fashion. Boot the live CD, select Backup or Restore from the Home screen and follow the wizard through the proces of choosing your backup location and restoring your snapshot.
The file that the restore process searches for is the DATE.backup file, where DATE is the date of the backup. You’ll see several files in the backup location. First, is the DATE.backup text file that lists your disk’s partitions (sda1, sda5). Second, is the DATE.mbr file, which is the master boot record file that is not text and shouldn’t be edited or altered in any way. Third, is the DATE.sfdisk text file that describes the disk’s physical layout and filesystem types. It looks like the output of a sfdisk -l command. Next, is the DATE.size text file that provides the restore system with the exact size of the original disk. The remaining files are the compressed partition backup files (DATE_part1.000, DATE_part5.000).
The restore process will overwrite your selected target disk and all of its contents. Once complete, you can reboot your system without the live CD and work with your restored system.
Redo offers you an elegant and complete backup and recovery system. The only flaw with Redo, if there is one, is that the process is an offline one, meaning that backups must take place using the live CD. This process, while ensuring a complete backup of a quiescent system, is a bit offputting in a production environment. The remedy for the situation is to use Redo after you install the system, its updates, and applications to make a complete backup of a pristine system. Once the system is up and running, install a backup agent to take backups of all changed files so that the restore process is fast and efficient. When you have to take a Mulligan on a failed system, Redo makes the job easy and pleasant.
Taking a Mulligan is the illegal but somewhat accepted practice of redoing a failed shot in golf.
Kenneth Hess is a Linux evangelist and freelance technical writer on a variety of open source topics including Linux, SQL, databases, and web services. Ken can be reached via his website at http://www.kenhess.com
. Practical Virtualization Solutions by Kenneth Hess and Amy Newman is available now.