Data recovery is a computing term that refers to the process of retrieving once-inaccessible data from a damaged, corrupted, or infected storage system. This process is an option only when data cannot be accessed in the usual way.
Data tends to be recovered from external sources of storage, such as solid-state drives (SSDs), cloud-based storage, USB drives, CDs, external hard drives, or other electronic devices.
Sometimes, recovery is necessary because the storage device is physically damaged. In other cases, the storage system cannot be opened or accessed by the operating system.
The most common reasons for data recovery include:
- Operating system failures
- Damage to the device or drive failure
- Accidental deletion of files
In the first case, the objective is to copy all necessary files to a different secure storage drive. Potential solutions in these cases include using a Live CD, which enables the user to mount the system drives, backup drives, or removable media, moving files from the system drive to the backup storage through a file manager. Disk partitioning, with valuable files stored in a partition, can make this process easier.
When a disk drive fails, whether because of a compromised file storage system, partition, or disk drive failure, data is more difficult to recover as it is hard to read. Some potential solutions may include initiating a repair, partition table, master boot record, or software-based recovery. Both hardware and software recovery methods are available, depending on the issue at hand. Replacing hardware on a drive that has sustained physical damage or replacing software may allow for data recovery. When the drive has failed and will never function again, the goal is to salvage as many readable files as possible.
When files are accidentally deleted from storage, they may also be recovered by different means. Firstly, when manually deleted files are not necessarily removed immediately from the drive’s memory. Instead, it’s only references to the deleted files that are removed. The space these files occupy may be made available to be overwritten by new or modified files. Though the user cannot typically see these deleted files using their standard file management system, the file data still exists on the drive. Therefore, they may be recoverable.
Four Phases of Data Recovery
There are four phases involved in the data recovery process. The order and significance of the phases may vary according to the type of data corruption and/or loss and the recovery process required. They include:
- Phase 1. During this phase, the hard disk drive is repaired so that it is running in some capacity suitable to allow the salvaging of data.
- Phase 2. The drive is imaged to either a new drive or an image file of the disk drive. Getting data safely off the drive is a priority, so using a faulty drive should be avoided.
- Phase 3. File recovery occurs at this stage, whether via software, partitioning, or another method. The drive is essentially copied to a new location where data may be accessed.
- Phase 4. Damaged files are repaired. If a file comes from a damaged sector of the drive, it may require repairs.