Definition
The action or process of regaining possession or control of something lost and stolen.
Disaster Recovery for Linux
There is no bootable Linux system on HDD in a disaster situation; therefore it is always a good idea to backup the bootable Linux system on removable media for example on floppy disks. For example if the hard disk fails, or if an important file is accidentally deleted. No matter what the cause is some recovery procedures will be needed.
The first step to recover from a disaster is to make a custom boot disk. It is not sufficient to just copy the standard boot disk image from the Linux cd rom because it will not necessarily have all the Kernal support configured. First log into the root shell session by using the cd / command and inserting a floppy disk. Then examine the /etc/lilo.conf to find the Kernal identity and use the mkbootdisk command and device /dev/fd0 with the string, example 2.2.5-15, found in the /etc/lilo.conf. The uname –a command can be used to display the Kernal version. After the successful completion of that step eject the disk and write protect it.
Another way to recover from a disaster is to make a rescue disk. The rescue disk is taken from the image in the linux cdrom. It is not like the custom bootdisk where an examination of the /etc/lilo.conf is done. What makes the boot disk created for the system valuable is that it contains the special drivers, such as SCSI drivers, that may be required to boot the system.
Another alternative to recover from a disaster is to create a Tom’s Root Boot Diskette. The tomsrtbt distribution may be done on the internet: A complete Linux system on a single diskette. To create the diskette set the browser to http://www.toms.net/rb/ and download the latest version. To prepare the emergency boot disk, place the zipped tar file into a directory such as /usr/local/src and follow the install procedures. The tar file is a versatile archiving utility that is not limited to strictly tape backup. TAR files can be stored locally as files, and sent over networks as a method of back up. The package squeezes an amazing number of Linux utilities onto a single 1.7 MB floppy by using high compression.
Conclusion
No matter what method used to back up the Linux system it is very important to take caution when dealing with Kernal config files. Always use the man command before using a command so the right syntax and option are used so that an important file isn’t deleted.
Data Recovery
Data recovery is the process of restoring data that has been lost, accidentally deleted, corrupted or made inaccessible for any reason.
In enterprise information technology (IT), data recovery typically refers to the restoration of data to a desktop, laptop, server, or external storage system from a backup.
The data recovery process may vary, depending on the circumstances of the data loss, the data recovery software used to create the backup, and the backup target media. For example, many desktop and laptop backup software platforms allow end users to restore lost files themselves, while restoration of a corrupted database from a tape backup is a more complicated process that requires IT intervention. Data recovery can also be provided as service. Such services are typically used to retrieve important files that were not backed up and accidentally deleted from a computer's file system but still remain on disk in fragments.
