Starting with 4K random reads, the results of adding seven additional drives is immediate.
The 0ctet of Crucials is able to hit 369K IOPS at QD32/QD64. That’s just about perfect scaling, merely a few thousand IOPS shy of 375K (8x the 46.9K IOPS a single M4 can do). So far, so good.
The M4s don’t quite scale perfectly with random writes at higher queue depths. Two, three, and four drives compound well, but after that, performance begins somewhat poorly.
Here are some 4K latency charts for 1, 4, and 8 drives. No surprises here.