Stripe size and stripe width
RAID Recovery - Stripe size and stripe width
Striping, used by different RAID levels, improves performance by breaking up files and spreading them across multiple disks. Striping implementations and the performance of array depend on two parameters.
The first important parameter is the stripe width of the array which refers to the number of stripes that can be read or written at the same time. The number of parallel stripes depends on the number of disks in the array. Likewise, the read and write performance of an array goes up or down depending upon the width of stripe. One gets better transfer performance from an array comprising of 8drives of 20GB than an array comprising of 4 drives of 40GB. The drawbacks of such arrangements are that they are costly and require a lot more power supply.
The second crucial parameter is the stripe or block size of the array. Stripe size refers to the size of stripes written to each disk in an array. It could be anywhere between 2 kiB to 512 kiB or even higher. However, apparently, it is very difficult to measure the impact of stripe size upon performance. Decreasing the stripe size increases the data transfer performance, but decreases the positioning performance. On the contrary, increasing the stripe size decreases the transfer performance and optimizes the positioning performance. This process can be significantly influenced by the use of controller.
Now, the question might arise, ‘what stripe to use for my Operating System’.
In general, larger stripe is considerably better, but small stripes can be upwardly compatible in their usable areas. In an application where smaller number of bigger files is expected to read fast will ideally prefer smaller stripes. A careful selection should be made that is certainly not hypothetical.
