If you look at our Btrfs benchmarks on Linux 2.6.32, you will see that the EXT4 file-system consistently outperformed Btrfs at every client count stepping. With the Linux 2.6.33 kernel the game has changed entirely as Btrfs is now outperforming EXT4! When running with one and six Dbench clients the performance was close, but starting with 12 clients and especially going forward with 48 and 128 clients this experimental file-system really blasted ahead. Between 48 and 128 clients, the Btrfs file-system took a much larger hit than EXT4, but still the Oracle file-system was faster. At 48 and 128 clients is where the Btrfs file-system with its transparent compression was at an advantage.
Btrfs was marginally faster than EXT4 with the FS-Mark test when running with 1000 files of 1MB size. Btrfs was faster by just about 3%, but when enabling compression the speed increased by 14% on top.
The performance between EXT4 and Btrfs was tied when running FS-Mark with 4000 files in 32 sub-directories of 1MB size, but again Btrfs with the compress mount option maintained the lead.