RAID (redundant array of independent disks) is a disk system that contains multiple disk drives, called an array, to provide greater performance, fault tolerance, storage capacity, at a moderate cost. While configuring your server system, you typically have to make a choice between hardware RAID and software RAID for the server’s internal disk drives.
RAID levels 0, 1, and 5 are typically implemented with SQL Server.
RAID 0 — RAID 0 offers no redundancy or fault tolerance, but instead helps improve performance by striping across multiple disks. RAID 0 also allows you to use the combined storage capacity of both disks.
RAID 1, also known as mirroring, provides fault tolerance by making a bit-for-bit copy of your data on two disks. While this provides basic redundancy and can improve Read performance (by having two separate disks available to read from), you might suffer minor loss of Write performance, since the data will have to be written across both disks.RAID 1 has 50 percent storage overhead.
RAID 5 — RAID 5 is one of the more common implementation types of RAID, utilizing three or more disks. RAID 5 is also called striping with parity, because as it stripes across multiple disks,it writes a parity block on each stripe that allows the data to be rebuilt in case of a disk failure.RAID 5 is considered a good option for most scenarios because it provides fault tolerance and
improved Read and Write performance and has a relatively low storage overhead. Because the available capacity on a RAID 5 array is n – 1 (n being the total number of disks in the array), the storage overhead decreases as the number of disks in the array increases.
RAID 10 — RAID 10 (also sometimes known as RAID 1+0) is the cat’s pajamas of RAID, and is considered the optimal design solution for SQL Server database files. RAID 10 requires a minimum of four disks and essentially stripes data across two mirrored sets. So let’s say, for example,that you have four disks: a, b, c, and d. Disks a and b will be used to make one mirrored set, which we’ll call ab, and disks c and d will be used to make the cd mirrored set. The two mirrored sets are then part of a new striped set, so when data is written to the array, it is striped across ab and cd.
Which RAID is suitable for SQL server
