RAID 1 advice and questions

So I've been building and repairing computers for many years now but I've never considered doing RAID before.

Currently I'm running my OS off of an SSD but I have three 500gb drives lying around that I could use in RAID.

I'm thinking of doing RAID 1 because they aren't the newest drives and I'd like that redundancy.

And I've been told that I should only do hardware RAID but I do believe my motherboard does that (P8Z77-V Pro if you want to check).

My questions are:

  1. Is it worth doing with three drives and not two? The third drive I will have to take stuff off of so if it's not worth the performance I won't bother.
  2. Can I then use my SSD as caching (for that RAID array) as you could with a normal drive? (and is it going to increase performance)
  3. If I can't use my SSD as caching, is it worth changing over at all or should I just stick with my SSD?

 Edit: General advice is also more than welcome.

All depends on your OS. Three drives gives you better performance in RAID 5 than a RAID 1 config, especially if you have a hardware RAID, because that will have it's own processor to do the parity computation. It would suprise me though if your motherboard has a hardware RAID on board, most of the time it's a RAID capable SATA controller that still runs on the CPU for parity calculation, and not a real RAID backplane with it's own processor.

SSD or part thereof can be used for caching, also through software. Depending on the configuration, multiple options are available. It's going to increase security more than performance, but it will also increase performance.

Running the OS on an SSD is the single most efficient performance boost in the last 5 years in mainstream PC hardware, imo you should definitely keep running your OS on the SSD, but even if you have a 32 GB SSD, / can't be more than 20 GB on even a fully loaded system, which leaves plenty space for caching the RAID storage pool.

I'm not going to bother with any RAID at all unless it will be faster than the SSD I'm running off currently, which from your post it sounds like it won't be.

It's a 120gb Kingston HyperX SSD (I think the SSDs are still called HyperX aren't they?) so the performance is good and the size is good enough to not have to worry about it.

I don't have any data that I need to worry about speed for apart from the OS so the three 500gb ones will just go into regular storage use. The only other thing I want fast is Steam games and they're on a 1tb Caviar Black, so there's adequate speed there.

The purpose of RAID 1 is to have an array of backup on a budget. This level only supports 2 hard drives. So a 3rd drive in the array would be meaningless. With RAID 1 you'll lose some of the performance. So if you want to populate 3 drives in an array, use RAID 5. You will also get a better performance off it than RAID 1, with the cost of 1 drive. And remember, make sure the drives are all exactly the same.

General advice: raid 0 another ssd.