Benchmarking hardware RAID vs. Linux kernel software RAID

http://www.linux.com/feature/140734
Benchmarking hardware RAID vs. Linux kernel software RAID

For the hardware test I used an $800 Adaptec SAS-31205 PCI Express 12-port hardware RAID card. For software RAID I used the Linux kernel software RAID functionality of a system running 64-bit Fedora 9. The test machine was an AMD X2 running at 2.2GHz equipped with 2GB of RAM.

(............................)

For RAID-10 using a smaller block size such as 256KB you get a noticeable
difference between hardware and software in rewrite performance. Hardware
beats out software substantially in output for parity RAID, with hardware
being 66% faster for block output and 20% faster for rewrite performance in
a 256KB chunk RAID-6. Therefore if you want performance and the capability
to sustain multiple drive failure at the same time you should investigate
hardware RAID solutions. Aside from the benchmarks, the hardware RAID card
also supports hot-plug replacement, mitigating downtime to swap out dead
drives. Based on these test results you might consider buying some cheaper
SATA ports and stripe two software RAID-6 arrays instead of buying a
hardware RAID card with the same budget.

http://en.wikipedia.org/wiki/Redundant_array_of_independent_disks
RAID

http://en.wikipedia.org/wiki/Standard_RAID_levels
Standard RAID levels