Suraj Rai asks on Twitter:
@duncan any thoughts on Thunderbolt devices like Promise instead of a NAS. Speed-wise presumably much faster than Gigabit cap?
Oh yes, Thunderbolt devices like the Promise RAID blows through the Gigabit cap with ease. Sequential read/write performance on a directly connected Promise Pegasus is about 5-6 times what you can get over Gigabit Ethernet, using AnandTech’s numbers.
If the sole criterion is speed, then a directly attached RAID wins every time, no doubt about it. The downside is that once you format a RAID on a Pegasus or the like, you can’t expand it later. In my case, I want to be able to access my archives at high speed, but the ability to expand my archive volume without forcing a copy to a new array trumps absolute performance.
I actually see the two—NAS and directly attached RAID—as being complementary in many ways, especially in a layered data environment like I have. I wouldn’t be surprised if I end up with some sort of Thunderbolt array attached to a new Mac Pro in the future. But that disk would be for working on live projects on, not for archival purposes.