We’ve touched on RAID arrays in our last two articles and received a fair few questions about how difficult it is to set up a RAID and just what it entails for the user. The fact is, RAID isn’t the big bad wolf the name and capitals make it out to be.
First things first, RAID stands for “redundant array of inexpensive disks” which should give some impression of just how this whole affair should run. Ideally we’d like to keep the whole thing nice and cheap, but offer some more options with your storage.
You’ll also need to determine where you want to keep all your data. If you’re looking to set up a RAID array inside your current desktop then it’s likely doable, but you could well run into some trouble with RAID support. It’s far easier to set up a RAID somewhere else in the house on a machine running FreeNAS and make sure you keep a regular backup. Ideally, you’d use something that will automate your backups for this kind of setup, along the lines of Norton Ghost or Acronis TrueImage.
For now though, we’ll assume you want to go internal 🙂
Setting it up:
Ideally before you get into this you should pick up at least two identical drives. You may want them to be identical for some RAID setups, but it does depend on how you want to run with the whole thing, there are RAIDs that’ll be perfectly happy with odd sized discs and others that will see you losing out if you’ve got some discs bigger than others. It’s a lot easier if they’re all the same size.
If you’re interested, we do a Samsung Spinpoint F1 at 1TB for €79, here.
Alright, once you’ve got your disks physically installed in your machine, you’re already through most of the awkwardness. What you’ll want to do from there is power up and jump straight into your BIOS settings (which will vary depending on your machine, but you’ll have to press a key during startup to get the whole thing going). Once you’re in there you’ll want to make sure that any SATA ports you’re not using are disabled, because they might be picked up as unreadable discs later. While you’re there, enable RAID if it’s not already on.
On your next boot you should have an option to open up your RAID configuration and have a look around at what’s inside. Depending on your RAID controller you’ll be given a few options. The most likely ones for us to use are RAID 1, RAID 0 and RAID 5. Remember that setting this up is going to wipe your disks, so we’d recommend you don’t do this with your existing system disk as a just-in-case.
RAID 1 is probably the simplest to explain, so we’ll go from there and work into more complicated things. Fundamentally, RAID 1 is just a straight mirroring across drives. Everything you write is written to both of your drives. There’s nothing more complex to it, but it does mean you always have a 100% current backup if either of your disks fails. It’s the mother of all backups and offers some pretty foolproof data recovery. Unfortunately, if you end up with a software issue or deleted documents, RAID 1’s mirroring isn’t much help, so you might want to keep a separate backup as well.
Attaching diagrams makes sure people don’t get lost in word soup.
RAID 0 does pretty much the polar opposite of RAID 1. It allows for the distribution of data across multiple disks in the array. The pleasant thing abut it is that you get the speed of having two drives writing whenever you’re writing and reading from two at once, so you’ll experience a general performance boost in those respects. The down side is that you’ll lose out on reliability. The big issue with RAID 0 is that it not only offers no protection from failure, but if any one drive fails the whole array is rendered useless… so tinker with care.
The diagram below is clearer than I can ever be.
RAID 5 is going to require one more disk, for those interested. While it does need three discs, it also combines favourable elements from both RAID 0 and RAID 1. Basically, you gain some failure insurance at the cost of one disc. The nice thing about RAID 5 is that if you throw in a heap of equally sized discs you’ll find our total storage capacity is reduced by the size of one disc. It has the benefit of adding space and reliability without a massive increase in cost (as long as you’re just picking up relatively cheap 1TB drives).
Check out the diagram if this is incomprehensible jibberish 🙂
Once you’ve pushed through all of the above and selected what kind of RAID you’d like to run you’re pretty much home free. Just remember that depending on your choice of array you’ll either be much better or far worse off when it comes to hard drive failures. In that respect we really do recommend either RAID 1 or RAID 5.
The knowledge that a failure could have been avoided with relative ease at the cost of some space generally compounds the sinking feeling that goes with a drive failure. Far better not to use RAID 0 unless you’ve got mountains of data about that you don’t mind losing.