As I threatened to do earlier today, I've run ZFS up against the PostgreSQL benchmark, along with ext4 and ZFS. (You may remember I did this a while back, looking at ext2/3/4, btrfs and xfs) I ran the results on Ubuntu 11.04 with Pg 9.0 and Ubuntu 11.10 beta with Pg 9.1. In the following results, the first combo is called "natty" and the second one "oneiric". The latter combination showed a considerable performance improvement overall - although I didn't investigate to find out whether this was due to kernel improvements, postgres improvements, or virtio improvements. The results are measured in transactions-per-second, with higher numbers being better. ext4 (data=writeback,relatime): natty: 248 oneiric: 297 ext4 (data=writeback,relatime,nobarrier): natty: didn't test oneiric: 1409 xfs (relatime): natty: didn't test oneiric: 171 btrfs (relatime): natty: 61.5 oneiric: 91 btrfs (relatime,nodatacow): natty: didn't test oneiric: 128 zfs (defaults): natty: 171 oneiric: 996 Conclusion: Last time I ran these tests, xfs and ext4 pulled very similar results, and both were miles ahead of btrfs. This time around, ext4 has managed to get a significantly faster result than xfs. However we have a new contender - ZFS performed *extremely* well on the latest Ubuntu setup - achieving triple the performance of regular ext4! I am suspicious that ZFS may not be using any "barrier" coding though - and if ext4 has those disabled, it surpasses even ZFSs high score. Oddly, ZFS performed wildly differently on ubuntu 11.04 vs 11.10b. I can't explain this. Any ideas? Cheers, Toby