Quote Originally Posted by deanjo View Post
Well the biggest performance hit is barriers. If you wish to have close to Ubuntu's Ext3's performance with EXT4 just mount the filesystem with nobarriers as mentioned
barriers do not explain the 50% drop in 2GB IOZone read performance.

Also, the article tested with nobarriers in 2.6.33-rc4, and although it helped the TPS for the PostgreSQL test, it still had a significant performance drop.

I think there must be other important issues than just barriers.