Do I want a RAID?

Question for Howard.

If I do, how do I go about setting one up? I have four external hard drives now, and they're so dead cheap ($80) I could easily see buying a couple more.

That depends on what kind of RAID you want. There are some for speed and some for safety.

If it's speed you're after, go for SSD instead; there is no RAID configuration that can give you the same increase in performance.

If it's safety you're after, some RAID configurations are great, but they diminish your performance, unless you buy specialized components (special drives, controllers, etc.), then you're into really big bucks.

The only RAID I see any value in today is a simple striped RAID 0 with two drives. If Apple's back-up-every-time-the-platter-spins (I forget what Apple calls it) works as advertised, I wouldn't even bother with RAID 0.

Yeah thanks. Speed is not an issue.

It’s entirely data security. Of my five drives, two are 3Tb externals which are used for 1) data storage, primarily music, video & photo files which are important but not unloseable, and 2) Apple’s Time Machine incremental backup. Does that back up everything, or just the main computer hard drive?  I have the main computer drive (I believe 2Tb) with all my apps. That’s unlosable and backed up.

Then I have a couple 1Tb external drives that are used for ancillary stuff, entirely loseable.

What I was thinking was putting some redundancy in my external drives (leaving the backup drive on its own). As I understand RAID-0, it does not provide redundancy at all. It simply distributes data so drive failures have limited scope. It takes a RAID-1 or above to provide survivability of data in a failure.

But hell. Music files are expendable. I have something like 27,000 of them.

NoCoPilot wrote:

Apple’s Time Machine incremental backup. Does that back up everything, or just the main computer hard drive?

If I remember correctly, you can configure Time Machine to back up whatever you want, even external drives. It may be that only the Mac Pro version of Time Machine has that capability. Don't really know.

Yes, RAID 0 is for performance improvements only. It actually increases the chances of a complete failure: if one drive fails, all drives are in a failed state and everything is lost.

RAID 1 is like having a backup program running constantly. All the drives are the same all the time (except for a failure). RAID 1 is the only valuable RAID configuration for the home user, in my opinion.

Remember that RAID is only for preventing loss from mechanical failure. It doesn't help at all if you catch a virus. Keep in mind also that not all computers support all versions of RAID - there are hardware requirements (unless you want to go with software-only implementation, which is a great big waste of time; really slows things down) and some configurations of RAID are really hardware expensive - consider eight drives with a controller for each of the drives. Big bucks, even with cheap drives.

So the answer is no. I do not want a RAID.

That may not be the answer.
If your computer handles hardware RAID and has room for two HDDs or SSDs, then RAID 1 might be a good move. You get real-time backup with little or no performance cost.

Ancillary question:

Is it possible to combine multiple external hard drives into one virtual drive? If I buy two 5Tb drives can I set them up as one 10Tb virtual drive?

Yes, you can combine two - or more - drives in various manners, but you always have one drawback: if any one of the drives dies, they all die.

Done through RAID 1 software?

Of course not. But why? Are you using an external drive to mirror an internal drive?

Every now and then I ponder the idea of digitizing my CD collection. I figure it would take 8-10 Tb and would only be worth doing if everything went into one searchable database.

But it's probably a project that'd take longer than I've got.

NoCoPilot wrote:

I ponder the idea of digitizing my CD collection.

Jeezus, where are you shopping? All my CDs are already digitized when I buy them. And my DVDs, too!

I’m still copying out the ones and zeros.

You should be concentrating on digitizing your LaserDiscs from analog. There's a challenge, if you do it manually.

And binary is only "one and zero" in certain places and societies. In other places, it is "'yea' and 'nay'," "'yup' and 'nope'," "'is' and 'ain't'," "'could be' and 'not a chance'," "'Hell, yes' and 'gimme a break'," "'damn right' and 'no fucking way'."
Well, you see where I'm going with this so I will stop and go get the garbage bins from the street.  This will be the first time in twenty years that I will be able to do that without using my truck to get down the hill and back (see thread, "Thinking about moving").