Originally Posted by
AceNZ
I updated the Intel firmware -- no noticeable change in performance.
I moved one of the 9260s from an x8 slot to an x16/x8 slot, next to the other 9260 (which is in an x8 slot, since the x16/x8 next to the video card is blocked by the audio cable).
The 4KB random performance unfortunately went down as a result. Sigh.
I'm mostly using two iometer tests: 4KB random reads with 2W, QD128 each; 128KB sequential reads, 1W, QD128; both with a 1GB test file. I generally used a 32K strip size. I tried a number of different configurations; here are my best numbers so far:
Single drive:
random: 38378 IOPS
sequential: 260 MBps
So far, so good: both random and seq are above Intel's specs of 35000 and 250, resp.
The "x" multipliers below are factors compared to a single drive.
Bootable:
random:
-- 8 drives: R80 --> 145916 IOPS (3.8x)
-- 16 drives: 8R0 * 2 S/W R1 --> 174186 IOPS (4.5x)
sequential:
-- 8 drives: 8R0 --> 1570 MBps (6.0x)
-- 16 drives: 8R0 * 2 S/W R1 --> 2305 MBps (8.9x)
Not bootable:
random:
-- 16 drives: 8R0 on each of 2 controllers --> 194639 IOPS (5.1x)
sequential:
-- 16 drives: 8R0 on each of 2 controllers --> 3144 MBps (12.1x)
While it's disappointing that 8 drives on one controller don't scale to 8.0x, the shocking thing is that going from 8R0 on one controller to 8R0 on two controllers (8 vs. 16 drives) only results in a 33% performance improvement, when it should be an easy double since there's no additional RAID logic or per-controller load.
My hope for this project was at least 200K IOPS (5.2x) for 8 drives, with near-linear scalability for each added controller. The NF200s seem to be the most likely culprit. Damn.