RAID (Redundant Array of Independent Disks) storage is a method of storing the same data on multiple hard disks. However, to an operating system, a RAID appears as a single, logical hard disk.
RAID storage uses disk striping, which is the technique of partitioning the storage space of each drive into units. The stripes of all the disks are interleaved and addressed in order.
In a single-user system, where large records are stored, the stripes are usually small (around 512 bytes) so that a single record spans all disks so that all the disks can be read at the same time and can thus be accessed quickly. In a multi-user system, a wider stripe is used to give better performance.
Advantages of RAID Storage
There are three main functions, or advantages of a RAID system, namely:
- Capacity – two hard drives can be linked together as a single drive. This effectively creates a virtual drive with twice the original capacity.
- Performance – When two drives work as one, the controller can separate a chunk of data into two parts, putting each on a separate drive. This has the effect of doubling the performance of writing or reading of data.
- Security of Data – Data can be cloned, so that the same data is saved to both drives. Thus, if one drive fails, the data is still stored safely on the other drive.
What are RAID Levels?
The ways in which data is distributed across the drives are referred to as RAID levels. There are approximately 12 levels available, but most small and medium-sized businesses will only use about six. Choosing which levels are right for you depends on the type of application data, how critical that data is, and the number of users who will be accessing that data.
Which Level is Right for My Business?
Of the six levels most commonly used, RAID 5 is by far the most common for business servers. It offers better performance and increased fault tolerance. With RAID 5, data and parity are striped across three or more disks. If one of these disks starts to fail, data is automatically and seamlessly recreated onto the remaining disks.
It’s important to remember that RAID is not a backup strategy in itself, but could be part of your total disaster recovery solution. Contact Mass Mountain through their website
