While the delta between EXT4 and Btrfs had not changed much when switching from 2GB to 8GB writes, between 2GB and 8GB reads the delta had minimized and to the support of Btrfs. Btrfs was just 4MB/s behind EXT4 and when enabling transparent zlib compression it boosted the read speed by 5MB/s, which put it barely ahead of EXT4.
Btrfs turned back to annihilating the EXT4 file-system when looking at the random write performance using Threaded I/O Tester. Btrfs was 11x faster than EXT4 with 16 threads of 64MB random writes! Utilizing transparent file-system compression though actually led to a degradation of the Btrfs file-system performance with this random write test.
With PostgreSQL the Btrfs performance continued to suffer like in past tests and using transparent compression was to no advantage. EXT4 was 4.5x faster than Btrfs with the PostgreSQL database test.
Like our Linux 2.6.32 kernel tests, EXT4 beat out Btrfs with PostMark by a sizable lead, but when enabling transparent zlib compression the experimental file-system was the winner by a small margin.