I got bit HARD today. I don’t think it will leave a scar, but still.
At 6AM this morning (Sunday), the adding of 3x750GB drives to an existing 4×750 RAID 6 array completed. After starting 8AM Saturday LAST WEEK. Effectively it took 8 days to get the capacity expanded. After all that waiting, I still only had 2TB available, when 7x750GB should give me 5×750 in effective space in a RAID 6 array. So why the missing 1.4TB? Time to troll.
After getting bounced around a bit between FAQ entries, trolling yields a hook on Adaptec’s site: “Microsoft operating system support for greater than 2TB RAID arrays“. Of course that links off to a nice prescriptive KB: Q302873.
Turns out that you need to have the drive use a GUID partitioning table instead of MBR in order to use sizes over 2TB. So I’ve got to remove all partitions on the volume, and change the scheme over to GPT. That means more delays as I copy off about 1TB of data so I can wipe the volume.
Adaptec is slightly more forgiving in this situation, as the RAID 6 array doesn’t appear to require any modifications.
My advice to you: When creating large array volumes in Windows Server 2008 and later, choose the GPT scheme when initializing the drive in Windows.
All in all: This sucks. I hate getting bit, especially when I don’t see it coming.
Update: Turns out the problem was not specifically the GPT nature of the partiiton (although that would have become a problem). The Adaptec driver required updating. Using the 2008-10-06 driver, and the amd64 one in particular was exactly what the doctor ordered. In the process of troubleshooting, I wiped the whole array and started from scratch, which proved useful getting up and running quicker with a full 3.4TB. Yippee…
Will add a few more 750B drives later this week, we’ll see how long the capacity expansion happens after that… Adaptec 31605 seems to show consistent lengthy times for OCE, one of the biggest disadvantages to this card 
In the end, two big bites. Ouch.
A self described geek, Chris' curiosity into how things work is often the motivator for new habits and ventures. A drinker of scotch, beer and vodka, and eater of meats as much as those green things beside them, Chris is as much at home behind the kitchen counter as being a diner at a local hot spot.