1. What does RAID stand for? Redundant Array of Independent Disks. Source: Steadfast.com 2. When would use RAID? When experiencing disk IO issues, where applications are waiting on the disk to perform tasks. It also provides additional throughput by allowing you to read and write data from multiple drives instead a single drive. Source: Steadfast.com 3. Define the following types of RAID:
RAID 0 (Striping) - RAID 0 is taking any number of disks and striping data across all of them. This will greatly increase speeds, as you're reading and writing from multiple disks at a time. An individual file can then use the speed and capacity of all the drives of the array. The downside to RAID 0 though is that it is NOT redundant, the loss of any individual disk will cause complete data loss. I would not recommend ever using RAID 0 in a server environment. You can use it for cache or other purposes where speed is important and reliability/data loss does not matter at all, but it should not be used for anything other than that. As an example, with the 5% annual failure rate of drives, if you have a 6 disk RAID 0 array you've increased your risk of data loss to nearly 27%.
RAID 1 (Mirroring) - RAID 1 is generally used with a pair of disks, though could be done with more, and would identically mirror/copy the data equally across all the drives in the array. The point of RAID 1 is primarily for redundancy, as you can completely lose a drive, but still stay up and running off the additional drive(s). You can then rebuild the array to a new drive off of the other drive with little to no downtime. RAID 1 also gives you the additional benefit of increased read performance as data can be read off any of the drives in the array. The downsides are that you will have slightly higher write latency, since the data needs to be written to all the drives in the array, and you'll