A server operating system plays a key role for the daily operation of an online computer lab. Ideally, we would like the server to run constantly without any downtime. However, in a real-life situation, there is a chance that a disaster can happen to the server operating system. For example, a hard drive crash can make the server unavailable for lab activities. After the crashed hard drive is replaced with a new one, you need to rebuild the server. It may take days or even weeks to rebuild a server.
Even worse, all the data saved on the server are lost. Since the server is shared by many users, the loss of data can have a negative impact on many users. When a server fails because of hardware damage, software failure, or human error, it is the lab manager's responsibility to recover the system as soon as possible. To reduce the negative impact caused from a disaster, we need to backup the server regularly.
With system backups, one can recover the failed system with the least amount of time and minimal data loss. In the following, we will discuss some of the concepts and practices related to computer system backup. In a system backup process, the current running system can be backed up to a storage device such as a tape drive, an external hard drive, or a storage area network (SAN) device. In addition to operating systems, other services such as Web sites and databases can also be backed up so that we can easily restore these services.
Some of the system backup methods are:
• Using the utilities included in an operating system. These tools are relatively easy to use and there is no extra cost.
• Using commercial backup software. Most of the backup software offers an adequate solution for network-wide backup. Some of them can also perform disaster recovery functions.
• Using a specially designed external hard disk such as the CMS external hard disk. This kind of hard disk can automatically back up a system even when a change is made to the internal hard disk. This type device is fast and easy to use, but may cost more.
• Using a hard disk image created by the disk imaging software. This method is good for initial installation of operating systems and application software on multiple computers.
• Using the backup BIOS and the boot sector which are the two components related to the system boot process. If any of these two components are damaged, the system can not be started. Backing up these components can at least help to get the system started.
Major IT companies such as IBM and Hewlett Packard (HP) provide backup utilities for their own computer products. Backing up the operating system is an important task in lab management. Sometimes, it is impossible to regenerate lost data. Often, system backup is the last resort to recover a failed system. Due to its importance, two examples will be used to demonstrate how to back up a system. The first example shows a backup process with a backup tool provided by an operating system, and the second example demonstrates a disk imaging process.