Professional Video

Similar to DAWs, non-linear editors (NLEs) are computer-based systems that facilitate digital video capturing and editing. They use random access (non-linear), non-destructive editing and have the ability to "undo" edits and move pieces of video. Traditionally, RAID arrays have been used in video production.

RAID Basics

Redundant Array of Independent (or Inexpensive) Disks is a way of combining multiple hard disk drives to create an array that behaves like one large disk drive. RAID is widely used in video applications because video often needs more throughput than one drive can sustain. Since video is extremely bandwidth-intensive, striping drives together (RAID 0) will help achieve the bandwidth required. More disks will yield greater bandwidth up to the limits of the interface. For example, the FireWire 800 bus tops out at 80MB/sec, while eSATA will sustain around 350MB/sec.

In comparison, audio is transaction-based, so you won't see increased performance when using striping (RAID 0) with an audio application. Audio file sizes tend to be smaller than video files so the time it takes for multiple drive heads to synchronize negates any bandwidth gains achieved in RAID 0. On the other hand, mirroring (RAID 1) can be beneficial in an audio application because it writes the data to two places at the same time. If one drive fails, the data is still present on the other.

RAID and Data Redundancy

Arrays are designed for performance and fault tolerance. Spreading data across multiple disks improves access time, and using RAID's fault tolerance reduces the risk of losing data if one drive fails. Below are common RAID levels, and descriptions and recommendations for their uses.

RAID Level Description Data Protection Minimum Drives Recommended Applications
0 :: Striping Data spread out across all disks. No data redundancy. Low 2 Video production and editing
1 :: Mirroring Complete data redundancy. Very high 2 Audio where data security is paramount
3 :: Parallel transfer w/ parity Data is written like striping. Parity data is stored on a separate hard drive. Very high 3 Video production & editing with extra data security.
5 :: Striping w/ parity Data is written like striping. Parity data is stored on dedicated blocks within stripe set. Very high 3 Video production & editing with extra data security.
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