The numbers were close in IOzone when it came to the 2GB write performance between Reiser4, EXT4, and Btrfs, but again this yet-to-be-mainlined file-system did the best. Reiser4 was writing at 85MB/s on average while Btrfs came in at 81MB/s and EXT4 was at 71MB/s. ReiserFS continued to come in last with a speed of 59MB/s.
When doubling the write size to 4GB so it was double that of the DDR3 system memory capacity, Reiser4 again showed the best numbers on this OCZ Vertex solid-state drive. Btrfs pulled in just behind Reiser4 while EXT4 was a ways back.
The same positioning occurred when using an 8GB write with the standard 4Kb block size.
While Reiser4 was the winner in five of the seven tests that we ran, other tests had to be left out since they could not successfully run on this experimental file-system. Though when time allows we will be digging into the Reiser4 code to see if we can make these other Linux file-system benchmarks run on Reiser4 or what the situation at hand comes down to. The tests where Reiser4 had ran but lost was with SQLite where it was half the speed of EXT4 but still faster than Btrfs and then the Compile Bench compile test where it was faster than EXT4 but lost to Btrfs.
For being a file-system not in the mainline kernel and does not receive as much development love as EXT4 and Btrfs, Reiser4 sure is running fast. Aside from some of the tests failing, we ran into no other issues with Reiser4. For those interested in testing out the Reiser4 file-system the kernel patches can be easily obtained from the Zen kernel patches or Andrew Morton's -mm branch. The Reiser4 file-system programs are packaged in Ubuntu's repository for easy setup and GParted can support setting up Reiser4 file-systems.
It would be great to see Reiser4 merged into the mainline Linux kernel if its remaining technical issues can be sorted out timely and judging from what we heard from Edward Shishkin last year it might be feasible to see Reiser4 in the mainline Linux kernel circa Linux 2.6.36 or 2.6.37. Before that would occur, however, Btrfs will certainly mature some more and likely become even faster. We are benchmarking the latest Linux kernel code on a daily basis and on EXT4 and Btrfs file-systems over at kernel-tracker.phoromatic.com or those interested can do it themselves using the Phoronix Test Suite and Phoromatic.
More details on the Reiser4 file-system can be found at Kernel.org.