> Not surprising at all. Read performance is similar between the two > setups as expected (appears to be limited by the PCI bus). Yes, reads are fine. > Streaming write performance is better because you are writing less > redundant data to disks, you can now stripe writes over 5 disks > instead of 3. Sounds reasonable. Write performance SHOULD be ~5x single disk for raid5 and ~3x single disk for raid10 in a theoretical best-case scenario, either should hit the PCI bus cap. In reality the ratios are more like 1x for raid5 and 0.6 -1.1x for raid10. It's just that I'd expected ~ identical and significantly better streaming write performance from both array configurations ... then again, if you think it over, raid5 will transfer 1 parity block per 5 data blocks (so 5/6 of the PCI bw are usable = 92MB) raid10 will transfer 3 copy blocks per 3 data blocks (so 1/2 of the PCI bw are usable = 55MB) Factoring in some contention / overhead my values might well be normal. It just means that the fabled raid10 only performs if you have high-bw buses, which this box sadly doesn't, or a hw controller where redundant blocks don't go over the bus, which the 3ware 7506 apparently isn't. I'll still go with raid10 for the 50% better random I/O, only less enthusiastically. Chris -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
