Got my LTO-4HH system yesterday, set it up and was preparing my first backup in less than 5 minutes. Really easy, it works. But...
The drive is noisy. Understandably, the tape spinning mechanism is loud, as most LTO, DLT, units are. But the cooling fan is stupidly loud for the small amount of air it actually moves. Quantum could have tried a bit harder here since this is in fact designed to be a desktop unit for the office environment. But I'll only be turning it on when I go to make backups anyway.
I ran my first backup tape last night after doing some preliminary tests. Both in the tests and with the backup, I have real issues with Retrospect and speed (or lack thereof). Retrospect makes no attempts to cache or pre-load data and seems to find itself slowing the drive while it moves from one file to another. My source volumes are not a bottleneck by any means and I can't seem to figure out why the performance is so bad. A 745GB backup with Verify, compression off, took 11 hours. I spent some time watching the drive usage during the backup and my RAID volumes were almost idle the whole time Retrospect was reading from them. The slower of the two can sustain almost 250MB/s and I can grade 2K DPX in real time from that drive in Color. The other RAID is a CalDigit HDPro that can handle around 450MB/s. So when I back up files from the two volumes, and it starts off at 1600MB/min and progressively gets faster toward the end of the tape, getting up to about 4000MB/min, with an overall average of 2300MB/min, I'm confused. This backup consisted of lots of small files - tons of still images. But there were a handful of 2GB R3D files and other stuff, maybe that accounted for the speed-up toward the end of the backup.
That's 26MB/s to start, up to 65MB/s by the end of the tape and an average of about 38MB/s. Quantum claims the drive is capable of 120MB/s. My LTO-3 unit I put in a small PC a few months ago is rated at 65 or 70 MB/s and I can sustain around 50MB/s to that unit. It's much faster on a lesser system. Although, I'm not using Retrospect. And the Mac version of Retrospect is pretty much junk compared to the PC version anyway.
Overall, I'm happy with this solution. The convenience of having 800GB tapes right on my Mac tower outweighs all the speed concerns. Hopefully this will improve with the new Retrospect X that's about to go into beta testing. Those of us who buy Retrospect 6.1 for Mac right now get a free upgrade when it's released.