by January 7, 2004 0 comments

While large organizations can build separate DR centers for protecting critical data, smaller organizations can build DR solutions from their existing data backup infrastructure. DR solutions are also available from vendors specifically for small organizations. Here we’ll look at how a small organization can build a DR solution from its existing backup infrastructure. The solution takes a full system backup and creates a DR bootable media from it, which can then be used to recover the system. 

Most organizations use tape backup to protect their data. The difficult part here is not doing the backup, but the recovery as it involves lot of complexities. The steps for doing it can be reinstalling the OS, configuring the hardware and installing drivers, loading the backup software, restoring the data, applications and system state from the backup medium. This makes the recovery process time consuming and increases the downtime between system failure and recovery. This means long hours of system unavailability, translating into direct business loss. What if you could automate this recovery process?

Disaster Recovery
The option here is Disaster Recovery, where you create disaster recovery bootable disks/CD to boot the system after a crash and restore the data and settings directly from the backup, without manually performing all these steps. Next question that comes to mind is how to create these disaster recovery bootable media? Most backup software such as Veritas Backup Exec, BrightStor ArcServer Backup, Tapeware, etc come with a disaster recovery option, and most of them support multiple OSs. Let’s see how to use some of these aspects of disaster recovery.

Test Setup
We used Veritas Backup Exec v9 with IDR (Intelligent Disaster Recovery) as the backup software and a Sony AIT-1 internal SCSI tape drive. IDR is an additional component and has to be licensed separately. We used a Win2000 Server running Active Directory and other services such as DHCP, DNS, IIS, anti-virus. Our aim was to backup the entire system on tape, replace the original hard disk with a fresh one and restore the original system on it using a disaster recovery CD and the backed up data. There are two ways to do this: one, you can have the tape drive attached directly on the server, and in other, it was on another machine somewhere else on the network. 

Select local or remote system to be backed up 

Local Backup
Backup Exec stores computer specific disaster recovery information in a *.dr file, where ‘*’ is the name of the computer for which the information is stored. This file is automatically updated whenever you perform a full system backup. For the local system backup start the backup wizard in the software and select the system state and all physical partitions on your system to backup. Backup of system state is essential for proper system restore. The wizard also asks for the backup options, here select full backup. Complete the backup wizard and run the backup job. After completing the backup of each physical drive and the system state the software will alert you to run the IDR wizard to create a bootable media with the most recent
*.dr files.

Network Backup 
For network backups, Backup Exec software with tape device drivers should be installed on the backup server, and Backup Exec agent with Disaster Recovery option on the system to be backed up, the domain controller in our case.

To backup the domain controller, start the backup wizard on the backup server. Then in the backup selection list select remote selections, choose the remote system (the domain controller) and select its physical partitions and system state. If you are not authenticated to the system, then it will ask you for username and password for the domain controller. After providing the password complete the wizard like above and the remote system files and settings will be backed on to the tape drive attached to the backup server.

Create Disaster Recovery bootable media
Backup exec lets you create disaster recovery boot floppies or CDs based on your requirement. It can also make bootable tape images for tape drives supporting booting from the tape. This feature is supported by few drives from HP. To make a boot media, run the IDR preparation wizard. Select the kind of boot media you want, floppies, CDs, bootable tape image. After this select the system for which you want to make the bootable media. For a local backup it is the local system and for remote backup, enter the remote system name, (the domain controller, in our setup). If you are making a boot CD or tape image, it will ask you for the OS installation CD of the system for which you are making the boot media. It will also ask for the Windows product key, which can also be entered later during recovery. If you have a CD-writer attached to your system, then you can directly burn a bootable CD, or save the bootable CD image (*.iso) and burn it afterwards. If you are making floppy disks, then it will ask you for path of the OS
installation files. Then it will create a set of floppy disks for use, the number of disks could be 5/6 depending on your requirement.

The system is recovered from a local drive or from a remote backup server

Recovering using the disaster recovery boot media
When the need arises to recover your system, boot the system using the disaster recovery floppy/ CD. If you are using floppy disks, you will also need the original installation CD. It will start a normal Windows installation screen and will let you define partitions on your new hard disk. After this the OS installation files are copied on the disk and the system restarts. Then the next phase of recovery begins. Initially it will look just like Windows installation but then a Veritas Intelligent Disaster Recovery for Windows Servers will ask you for the level of Wizard assistance. If you are doing a local recovery, it is good to choose the automated level and for remote recovery choose the assisted level. Click Next and select the disaster recovery file (*.dr) for your system. Next it will show you the partition layout of the original system. You can change the layout also, but making a partition smaller than the total data backed up for it will fail the recovery process. After this the restore method is asked, you can choose from locally attached media device or remote media server. Choose whatever is applicable to your setup. Then the system restarts and next it will install networking and other basic components of the operating system. If you are recovering from a local drive then it will show you the tape drives connected. If it is a remote recovery, then give the IP address or name of the backup server and username, password for it. One thing to note while doing remote recovery is that the software does not let you specify an IP address for the network card attached to system being recovered. So you will need DHCP service running on the network, for the machine to pick up an IP address during the recovery process. After you have selected the local drive or connected to the remote backup server, you will be presented with the backup sets on the tape for your system. A backup set is a backup unit like a physical partition backup or system state backup. While the automated recovery will restore all backup sets on the hard disk itself, assisted recover will let you choose and restore backup sets. Once you are done restoring the backup to your system, reboot and your system is ready to work.

Test the new system
Reboot the system and the first thing you will notice is that the new system is exactly similar to the original system. Log onto it and verify that all applications, configurations and data have been restored properly. In almost all cases you may not be able to find any difference. The new system worked absolutely fine retaining all user information and data, the active directory schema, network services and applications.

Advanced open File Option
An additional component of the Backup Exec software, it takes point-in-time static view of the volume being backed up, which lets you, safely backup files that are open during backup. 

This option is very useful, especially during full backups for disaster recovery as it ensures integrity of the files being backed up. So enable this option while taking backups. It can be done while creating a backup job.

The solution described in this article is the first step towards system recovery. You also need to work out where you want to store the backup. Ideally, in a remote location so that in case disaster strikes, your data is safe and ready to rebuild your systems. You might, for instance, register a bank locker to store your DR media, then you’ll also need someone reliable to carry it. Also you would have to work out with your vendors about providing you the required hardware/software when you need to put your systems back in place in case your server crashes.

Anoop Mangla

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