A volume is a storage unit made from free space on one or more disks. It can be formatted with a file system and assigned a drive letter. Volumes on dynamic disks can have any of the following types: simple, spanned, mirror, striped, or RAID-5.

A simple volume uses free space from a single disk. It can be a single region on a disk or consist of multiple, consecutive regions. A simple volume can be extended within the same disk or onto additional disks. If a simple volume is extended across multiple disks, it becomes a spanned volume.

A spanned volume is created from free disk space that is linked together from multiple disks. You can extend a spanned volume onto a maximum of 32 disks. A spanned volume cannot be mirror image and is not fault-tolerant.

A striped volume is a volume whose data is alternately stored across two or more physical disks. The data on this type of volume is allocated alternately and evenly to each of the physical disks. A striped volume cannot be mirror image or extended and is not fault-tolerant. The striped volume is also called RAID-0.

A mirror volume is a fault-tolerant volume whose data is duplicated on two physical disks. All of the data on one volume is copied to another disk to provide data redundancy. If one of the disks fails, the data can still be accessed from the remaining disk. A mirror volume cannot be extended. Mirroring is also known as RAID-1.

A RAID-5 volume is a fault-tolerant volume whose data is striped across an array of three or more disks. Parity (a calculated value that can be used to reconstruct data after a failure) is also striped across the disk array. If a physical disk fails, the portion of the RAID-5 volume that was on that failed disk can be re-created from the remaining data and the parity. A RAID-5 volume cannot be mirror or extended.

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