This time around I'm doing the Btrfs RAID benchmarks on four traditional HDDs (though separately also been working on Linux RAID tests on a 6 SAS drive server). For this testing I picked up for WD Green 1TB 3.5-inch, SATA 6Gb/s, 64MB Cache WD10EZRX drives. At Amazon they cost only $52 USD a piece and should be interesting to test in a four-disk RAID array.
Before the end of the month I didn't have the time yet to do the four-disk RAID 0/1/5/6 benchmarks on Btrfs with Linux 4.0, but thus far have done the RAID 0/1 tests on two disks. If you're curious about seeing those dual disk results of Btrfs RAID on Linux 4.0, I've uploaded the initial data to OpenBenchmarking.org.
Head on over to this OpenBenchmarking.org result file if you want a preview of these numbers of Btrfs on a single Western Digital HDD, then using two of the drives in RAID 0 and RAID 1. Stay tuned for the four-disk RAID results in the days ahead.
If you missed it last year, you might be interested in the older results of four SSD tests of Btrfs RAID 0/1/5/6/10 and Linux RAID tests of many file-systems.