A couple of years ago, I happened upon a decent deal on a LaCie "Biggest FW800" RAID. It was a 1TB model, with four 250GB SATA drives in it.
I won't get into the particulars about how the unit works or what its features are, but I will say that it has performed quite admirably for me, with no issues.
A few weeks ago, I inadvertently deleted a huge folder full of movies and television shows that I'd been holding onto just for convenience (I will sometimes put together "care packages" for friends with random or specific stuff on a few DVDs, and it's nice to have my favorites handy).
Since I knew I'd be able to re-download most of the stuff I'd lost, I got to thinking - "this thing is pretty much completely empty right now..." - and I decided that it was time to upgrade.
The four 250GB drives, when configured as a RAID-5, yielded about 680GB of useable storage. I figured replacing them with 1TB drives should net me about 2.8TB or so, in the same configuration. So I found myself a nice deal on a set of 1TB hard drives, and when they arrived, I installed them in the unit.
Here's where things got interesting...
When the unit began formatting/initializing the drives into the array, the LCD panel was reporting that the volume size was XXXX. Normally, this would report an actual number. Since the volume wasn't visible to the OS at this point, all I could do was cycle through the status reports of the individual drive modules on the LCD of the RAID. It recognized them all as 1TB drives.
After a couple of hours, the initialization finished, and the volume showed up on my machine - as a 2TB volume. Not 1.9, not 2.1, and sadly, not 2.8... But an even 2 terabytes.
My conclusion is this: these particular RAIDs simply cannot recognize drives larger than 500GB. This makes sense, because at the time of the unit's manufacture and for the [relatively short] time period that they were sold, the largest drives available were 500GB. Looking back at the literature, I found that this model was available in 1TB or 2TB configurations. It also looks like this model was only around for about a year or so, replaced by a similarly named (why do they do that?), similarly featured product.
I'm not that upset by my "loss" of space. After all, I more than doubled the amount I had in the first place. And I don't feel bad about the drives, either, as they will most likely find their way into a Drobo Pro one of these days.
Anyway, I just wanted to share my experience on the off chance that anyone else out there might have one of these units, and was considering the same upgrade plan I had. You can save a little money and go with 500GB drives, as that's as big as it'll use. Although, I'll bet that the formatted capacity of a 4x 500GB RAID would be closer to 1.8TB, so maybe 750GB drives would be the best. [shrug]