Data Mirroring, Striping with and without parity

Mirroring, Striping and Striping with parity are the three fundamental RAID techniques and the various RAID types (RAID 5, 6 etc) can use one or more of these techniques.

Data mirroring stores the same data across two hard drives which provides redundancy and read speed.
Upside: - Redundant - if a single drive fails, the other drive still has the data. Great on read I/O performance and read throughput because it can independently process two read requests at the same time.
Downside: - Your capacity is only half of the total capacity of all your hard drives expensive.

Striping the data distributes the data across multiple hard drives.
Upside: - Scales very well on read and write throughput for single tasks but it has less read throughput than data mirroring when processing multiple tasks.
Downside: - Rarely used by itself because it provides zero fault tolerance and a single drive failure causes not only the data on that drive to fail, but the entire RAID array.

Striping with parity solves the reliability problem at the expense of some capacity and a big hit on write IOPS and write throughput. Data is striped across multiple hard drives just like normal data striping but a parity is generated and stored on one or more hard drives. Parity data allows a RAID volume to be reconstructed if one (sometimes two) hard drives fail within the array.
Upside: - Data is safe – Loss of data is less likely
Downside: - Can be expensive – With drive capacities increasing – xTB is no longer available for use.

For additional information - understanding RAID
http://www.sunstarco.com/Education/RAID%20Solutions.htm

Please feel free to visit our web site for more information, we have an assortment of storage solutions that will take advantage of the technologies stated above.

www.sunstarco.com
800-663-5523
info@sunstarco.com