A spanned volume is a formatted

Disk formatting

Disk formatting is the process of preparing a hard disk drive or flexible disk medium for data storage. In some cases, the formatting operation may also create one or more new file systems...

 partition which data

Data

The term data refers to qualitative or quantitative attributes of a variable or set of variables. Data are typically the results of measurements and can be the basis of graphs, images, or observations of a set of variables. Data are often viewed as the lowest level of abstraction from which...

 is stored on more than one hard disk

Hard disk

A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

, yet appears as one volume.

Spanned volumes are a non-RAID drive architecture, and may be implemented in hardware or software; they may be referred to as Concatenation, SPAN, BIG, or JBOD, though this latter is ambiguous – JBOD may also refer to each physical disk being presented as a separate logical volume.

Drawbacks

Unlike RAID, spanned volumes have no fault-tolerance, so if any disk fails, the data on the whole volume could be lost.

Implementations

In Windows NT

Windows NT

Windows NT is a family of operating systems produced by Microsoft, the first version of which was released in July 1993. It was a powerful high-level-language-based, processor-independent, multiprocessing, multiuser operating system with features comparable to Unix. It was intended to complement...

, a spanned volume is called a volume set.
FAT16/32

File Allocation Table

File Allocation Table is a computer file system architecture now widely used on many computer systems and most memory cards, such as those used with digital cameras. FAT file systems are commonly found on floppy disks, flash memory cards, digital cameras, and many other portable devices because of...

 and NTFS

NTFS

NTFS is the standard file system of Windows NT, including its later versions Windows 2000, Windows XP, Windows Server 2003, Windows Server 2008, Windows Vista, and Windows 7....

 file system

File system

A file system is a means to organize data expected to be retained after a program terminates by providing procedures to store, retrieve and update data, as well as manage the available space on the device which contain it. A file system organizes data in an efficient manner and is tuned to the...

s may be used, and the volume can span up to 32 hard disks, and the system or boot partitions cannot be included in a spanned volume.