We’ve all dealt with data loss, whether it was a hard drive failure, data corruption or accidentally deleting a file. If you’ve ever experienced a major loss of data, you’ve probably wondered about data recovery — how does it work? How effective is it? How much does it cost?
Data loss can take many forms — accidental deletion, hard drive failure, software bugs, data corruption, hacking, even a simple power failure can cause you to lose data. And, of course, there are more extreme cases, like when a hard drive is recovered from a plane crash; amazingly, some data recovery specialists can retrieve data from storage media that’s been almost completely destroyed.
What is Data Recovery?
Data recovery is the process of salvaging data from damaged, failed, corrupted, or inaccessible secondary storage media when it cannot be accessed normally. Often the data are being salvaged from storage media such as internal or external hard disk drives, solid state drives (SSD), USB flash, storage tapes, CDs, DVDs, RAID, and other electronics. Recovery may be required due to physical damage to the storage device or logical damage to the file system that prevents it from being mounted by the host operating system.
The most common "data recovery" scenario involves an operating system (OS) failure (typically on a single-disk, single-partition, single-OS system), in which case the goal is simply to copy all wanted files to another disk. This can be easily accomplished with a Live CD, most of which provide a means to mount the system drive and backup disks or removable media, and to move the files from the system disk to the backup media with a file manager or optical disc authoring software. Such cases can often be mitigated by disk partitioning and consistently storing valuable data files (or copies of them) on a different partition from the replaceable OS system files.
Another scenario involves a disk-level failure, such as a compromised file system or disk partition or a hard disk failure. In any of these cases, the data cannot be easily read. Depending on the situation, solutions involve repairing the file system, partition table or master boot record, or hard disk recovery techniques ranging from software-based recovery of corrupted data to hardware replacement on a physically damaged disk. If hard disk recovery is necessary, the disk itself has typically failed permanently, and the focus is rather on a one-time recovery, salvaging whatever data can be read.
In a third scenario, files have been "deleted" from a storage medium. Typically, deleted files are not erased immediately; instead, references to them in the directory structure are removed, and the space they occupy is made available for later overwriting. In the meantime, the original file may be restored. Although there is some confusion over the term, "data recovery" may also be used in the context of forensic applications or espionage.
Of course, data recovery won’t always be possible; sometimes a system can be too corrupted or damaged to get much of the data back. However, data-recovery technology has become extremely advanced.
Data recovery software and specialists can do a great job of getting your data back, but it’s risky, time-consuming, and expensive. The best measure you can take to prevent long-term data loss is the one we’ve been advocating for a long time: make lots of backups!
To your success!