RAID Level 0: Striping
This lesson introduces RAID level zero and analyzes it with respect to different axes.
We'll cover the following...
The first RAID level is actually not a RAID level at all, in that there is no redundancy. However, RAID level 0, or striping as it is better known, serves as an excellent upper-bound on performance and capacity and thus is worth understanding.
The simplest form of striping will stripe blocks across the disks of the system as follows (assume here a 4-disk array):
From the figure above, you get the basic idea: spread the blocks of the array across the disks in a round-robin fashion. This approach is designed to extract the most parallelism from the array when requests are made for contiguous chunks of the array (as in a large, sequential read, for example). We call the blocks in the same row a stripe; thus, blocks 0, 1, 2, and 3 are in the same stripe above.
In the example, we have made the simplifying assumption that only 1 block (each of say size 4KB) is placed on each disk before moving on to the next. However, this arrangement need not be the case. For example, we could arrange the blocks across disks as shown in the figure below:
In this ...