Sorry to resurrect an ancient question, but I stumbled on this while looking for examples of Redundant Acronym Syndrome (RAS, or RAS Syndrome). While @chaos's answer is correct, it is lacking in justification, and I find it less than satisfying.
As we know, RAID stands for Redundant Array of Independent / Inexpensive Disks. An array of disks is a thing, so RAID is a noun, and you are free to use it like one. Array, meaning that once context establishes that we're talking about RAID, and you need a noun to refer to it, you can use "RAID" and "array" interchangeably, choosing whichever feels better in the moment.
I prefer to avoid "RAID array," but I find it less egregious than things like "PIN Number" because array isn't the last word in the acronym. If it were instead called Redundant Independent Disk Array, then I would object more strenuously to "RIDA array."
Like many nouns, you can also use RAID as an adjective to qualify related nouns (dog is clearly a noun, but when used in dog walker, it's an adjective):
- RAID volume: the logical software entity recognized by your operating system, representing (a portion of) the storage space offered by the array
- RAID controller: the circuits and/or software responsible for translating reads and writes for a RAID volume into corresponding reads and writes for the individual disks, as well as handling parity, repair, etc.
- RAID enclosure: a box, if present, enclosing all of the disks in the array, usually including a RAID controller and presenting itself to the connected computer as a single disk.
- RAID setup: the entire system (hardware components, connections, drivers, configuration settings, volume layout)
In the case of your actual question, @chaos's answer is correct: you configure the OS to boot from a RAID volume. Note that a single RAID array may comprise multiple volumes, so volume is not an appropriate way to refer to the set of physical disks. For that, I think array is the right choice, with RAID and disk array as the preferred backups. I do not have a strong objection to RAID array if that feels better in situ.