Raid-0 WD Raptor set-up

About a year ago one of my Western Digital Raptor drives died so they sent me a new one but in the mean time I ended up buying two WD Velociraptors. I've had these drives for a while and I finally decided to put them on Craigslist but I just got a question I'm not sure how to answer from a potential buyer.

"I have a Raid 0 question: My raid volume is built with Raptor 36 gig drives. It is using an Intel raid utility. Do you know if I can replace the bad drive with one of your 74 gig drives, let the volume rebuild, reboot, then replace the other 36 gig drive with the 2nd 74 gig drive , and have the raid volume automatically read 74 gig. Or since the original volume was 36 gig, would it just use both new drives as a 36 gig volume?"

I would rather not give an incorrect answer so I rather give it to someone with more knowledge on the subject.

Thanks in advance
-Lollies

RAID 0 only works with 2 or more identical HDDS of the same capacity

The problem with RAID 0 is that if one of the drives fail, your data is pretty much lost. There is no redundancy so even if you replace it with a drive, either equal or larger than the one it replaced, your striped set is pretty much corrupted.

Just so you understand, the RAID 0 setup is suppose to stripe data across the drives, effectively allowing you to have a logical disk the size of N times the size of your drive, in this case, N = number of drives put in a RAID 0 configuration.

The benefits of a RAID 0 configuration is disk access performance. In this case, you can get, theoretically up to N times faster access as your data is spread out across the N disks, and not bottle necked by 1 disk connection.

The 'ideal' performance is to use RAID 1+0 or RAID 10, where you get N/2 times the amount of disk space. The reason for this being 'ideal' is that you get the benefits of RAID 0 performance with RAID 1 redundancy, but it costs you twice the number of disks to get the desired size.

Others will say RAID 5 is an alternative. RAID 5 will give Striping and Redundancy through a Parity drive. This means you get N-1 times the disk space, where N is 3 or more, you need a minimum of 3 disks to achieve this. Performance here is dependent on how the RAID 5 is done, via hardware or software and how intense the data access is and things are setup. This allows for striping of data and redundancy, but you lose a little performance in due to Parity. RAID 5 and 10 have the benefit of affording to lose 1 disk. If you have the right kind of controller and drives, you can also do hot swapping of drives and rebuild your array, but generally that is on Server level hardware than on Home level computers due to cost and just simply the necessity.

The one thing I will suggest... Never use RAID 0. RAID 0 should only be used if you have to store temporary, fast access data. And by temporary, I mean, you don't care if you lose it. If you EVER use this on an OS or even as normal data storage, you better hope you back that data up religiously, because again, if even ONE disk fails in a RAID 0 array, you have no redundancy to recover. A fraction of a data lost on that drive is devastating.

Now, going back to your person's question... He seriously cannot rebuild his array with RAID 0, after describing all this, he just simply can't. Now if he wanted to rebuild or Mirror a perfectly fine Hard drive, his 36 gig to a 74 gig, he can in RAID 1, but he will not be able to re-mirror it back from the 74 gig to another 74 gig drive unless the disk was set up to be a Dynamic disk. I haven't tried this experiment per say, but by technicality, you can 'add' more space to a dynamic disk, whether or not you can do it this way, I have to differ to someone who has done it.

I think I'll take my chances with and stick RAID 0 anyway. Except I bought WD RE4s. They're almost as fast as velociraptors and the cost per GB is less, plus even though they're designed to be run 24-7 they're still backed by a 5 year warranty.. 3TB of HDD space, just as fast as a SSD, for $900... and so what if one of them fails? I've never been dumb enough to keep any file I consider valuable on a single machine anyway.