The table below shows some common terms used to refer to video/image resolutions.

We offer a variety of RAID methods on our DVR. At the time of ordering please let us know what type of RAID system you will need. Below is a description of the methods we currently offer.

A26. RAID Level 0

RAID level 0 offers no redundancy and is sometimes called striping. This RAID level offers the highest level of performance compared to the other RAID levels. It also offers the lowest cost per megabyte, as no extra storage is required for fault tolerance. A minimum of two hard disk drives is required and you can have as many drives in the RAID 0 array as are supported by the RAID controller card.

This level is good for applications that don’t require any data redundancy. For example, digital video editing is a common application for RAID 0. If one of the drives in the RAID 0 array goes down, the source can be recovered from the original videotape.

RAID level 0 provides highest performance for digital video. The more drives you add the better the performance you will get. Minimum 2 drives are requested.

RAID Level 1

RAID 1 is sometimes referred to as mirroring. RAID 1 is implemented with two drives. RAID 1 arrays are fault tolerant, since if one drive fails, the other drive still has the data to keep the system going. It is easy to rebuild a degraded RAID 1 array, as the data is available on the remaining drive.

We recommend RAID 1 for applications that have critical data. Depending on the RAID controller used, performance with RAID 1 arrays can be very good.

RAID Level 5

RAID 5 uses block level striping and distributed parity. The RAID 5 parity is used for fault tolerance. If one of the disk drives in the RAID 5 array goes down, data can be recovered from the remaining drives. In this case, the RAID 5 array is said to be “degraded”. A degraded RAID 5 array is not fault tolerant until the failed drive is replaced and the RAID 5 array is rebuilt.

RAID 5 has an advantage over RAID 3. Although both of these RAID levels have parity, RAID 5 distributes the parity over all of the drives to increase performance by decreasing the bottleneck to a single drive. RAID 3 uses a dedicated disk drive for all of the parity information.

The usable capacity of a RAID 5 array is equal to (the number of drives in the array minus 1) x (the capacity of the smallest drive in the array). Generally, the disk drives used in a RAID 5 array should all be of the same disk capacity. A RAID 5 array of three disk drives uses 33% (1 / 3) of its capacity for parity protection. However, this percentage drops as more drives are added into the RAID 5 array. For example, a RAID 5 array with 8 drives uses only 12.5% (1/8) of its capacity for parity protection.

RAID 5 is one of the most popular RAID levels being used today. RAID 5 is an excellent combination of performance, redundancy, and storage capacity. Some 3ware Escalade RAID controllers have the R5 Fusion , which offers the best RAID 5 performance on the market.

RAID Level 10

RAID level 10 is a combination of RAID levels 1 and 0. Drives are mirrored first (RAID 1), and then striped (RAID 0). A RAID level 10 array can sustain multiple drive failures.

Performance is very good with RAID 10 arrays, and redundancy is very high, but it comes at the cost of additional disk drives.