Got a 16TB volume mounted
uvitor,
Have you had any problems with your 6x4TB yet?
Carl.
After these encouraging news; I bought a second R6 to experiment. It came with the new Deskstar 1TB disks which have a single platter and 4k sectors. Strangely, the new R6 did not have the March firmware, even though it was purchased in August and the 1TB disks were manufactured in June (the date is printed on each Hitachi disk). The PROMISE firmware upgrade is REQUIRED to use use disks with 4K sectors (like 4TB). Only 1 and 2TB disks can operate in 512 byte/sector emulation mode.
To be on the safe side I installed Ultrastar 7k4000 disks; and have more than 10TB data loaded already. Works like a charm, only the 4TB disks consume twice as much. The Fan on the 6x2TB unit is 1100rpm (minimum speed) and hardly noticeable, on the 6x4TB unit it is 2200rpm and noticeable. Also the controller has +2C more according to the util (the controller is on top, so it collects the heat rising from the disk. I can run the 6x2TB without air-conditioning, but would not do for the 6x4TB if room temp exceeds 25C (77F). The case is noticeable warm too. Worst, the 4TB disks are really noisy - not just spinning louder; but also during access. I had this noise level last on my Apple2 using a 80MB MICROPOLIS disk. The disk drive resonates low-frequency noise when the disk is stepping between tracks.
I got my first 6x2TB in 9/2011 and so far no issues. Twice a disk (the same) did not spin up (and in this case the volume is not mounted); this is normal of any good RAID. If it would mount it would imply data was modified and you had to rebuild the broken disk. I did power off; and power-on and every time the disk #3 came back on-line. And because the RAID does not mount by default, this is the end of it. If the disk were really bad, one had to force the volume (not the disk!) to mount - IMHO this O.K., but should be possible from the GUI (is only possible from the command line). The new 6x4TB R6-unit is daisy chained to the first one. I do power-down every night; and it gets used almost every single day because it also hosts my iTunes library.
Speed (tested using AJA System Test) on the 6x4TB configured in RAID6 (=16TB useable) is 520MB/sec write and 580MB/sec read (same as original disks). A Finder copy of 32GB takes less than 2 minutes. Rebuild took 22 hrs - exactly double the time of the 7K2000 disks; expected as the speed of SATA and controller is the same - and disks are twice as large. RAID6 means 2 disks can fail without loosing data. The rebuild (22hrs) puts a lot more load on the R6 than I do during normal use; so this is a good choice IMHO.
I configured 4K sectors on the RAID-6; but the Promise tool would also accept it with 512 bytes = IMHO this is a bug because with 512 the software cannot address all the space; this is the reason that we have 4K sectors.
All in all, I would still recommend it if you need the space.
