Interesting question. The answer I came to, perhaps through lack of information and experience, is that there isn't a best 1.5tb drive. I decided that 1.5tb is too big, and that it's better to use more and smaller devices so I could get to raidz3.
The reasoning came after reading the case for triple-parity raid. The curves showing time to failure versus time to resilver a single lost drive. Time to failure will remain constant-ish, while time to resilver will increase as the number of bits inside a single drive increases, largely because the input/output bandwidth is going to increase only very slowly. The bigger the number of bits in a single drive compared to the time to write a new, full disk worth of bits, the bigger the window for a second-drive failure. Hence, the third parity version is desirable. In general, more drives of smaller capacity within reason for a vdev, the less exposure to a double fault. This led me to look at sub-terabyte drives, and that's how I accidentally found those 0.75GB raid-rated drives, although the "raid rated" wasn't what I was looking for. I was after the best cost/bit in a six-drive batch with a top cost limit. After reading through the "best practices" stuff, I clumsily decided that a six- or seven-drive raidz3 would be a good idea. And I have a natural leaning to stay !OFF! the leading edge of technology where keeping data reliable is involved. It's a personal quirk I learned by getting several scars to remind me. How's that for a mismash of misunderstanding? 8-) -- This message posted from opensolaris.org _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
