The various options for Linux® backup can be divided into logical and a physical solutions. Logical solutions include periodic full system backups and incremental backups, and physical solutions include using any type of media that is capable of storing data. If a device can store data, it can also be used for Linux® backup. Universal serial bus (USB), zip, tape, compact disc (CD) and digital versatile disc (DVD) writer drives can all be used to back up data. Network attached storage (NAS) is an option specifically for the backup of networks of all sizes.
Full-system backups are exactly what the name says: the backup of the entire system. They are generally performed periodically whether that is daily, weekly, monthly or yearly. The frequency depends on the amount of data in the system, the operations taking place and how often a full backup needs to be done according to the administrators in charge of task. Incremental backup systems only backup changes. For example, when data is updated in a file or new files are added, only those changes would be recorded, not data that has not been modified.
Linux® backup for single-user systems can often be accomplished by copying data to a USB drive, sometimes called a thumb drive, pen drive or USB stick. These devices can be purchased with low or high storage capacity, so they offer great flexibility for storing copies of data. Zip drives are not used very frequently, but they are an option for Linux® backup, as are tape drives and CD and DVD writers. The options for Linux® backup are not really that different from those that are available for backup under other operating systems.
When speaking of hardware for Linux® backup options, the various drives are mentioned, but the drives cannot be used without the actual media to which they write. For example, CD and DVD drives write to recordable (CD-R) and rewritable (CD-RW) discs. Tape drives write to special tape cartridges, and zip drives write to zip discs. All that is needed in terms of hardware for Linux® backup to a USB drive are USB ports. Networks that are backed up using NAS make use of a device resembling a cabinet that contains hard drives along with the circuitry that controls them and the software needed to manage them.
Options for Linux® backup depend not only on whether it is a question of a single or multi-user system, but also on the amount of data that must be stored and the technical knowledge of the person or persons responsible for the backup. CDs hold about 700 megabytes (MB) of data, and DVDs can hold as much as 4.4 gigabytes (GB). There are tape cartridges that can store up to 70 GB of data. If only 1 GB of data needs to be stored, a DVD can be an option, but a CD cannot because of its storage capacity unless that 1 GB of data could be compressed to no more than 700 MB. Although floppy disks are technically an option for backup, they are usually impractical because they store only around 1.44 MB of data.