EBS+RAID10+XFS slower than EBS+RAID10+EXT3 using MySQL?
Solution 1:
The XFS filesystem always requires tuning. Running a default mkfs and mount will result in so-so performance. You'll want to set your allocation group number at filesystem creation time. Disabling write barriers may make sense. Also pay close attention to your filesystem usage and mount options on the specific kernel series you're using. Some interesting defaults were recently backported.
Also check your I/O elevator settings. Take a look at some of the recommendations at: CentOS 6 doing lots more IO than CentOS 5
Solution 2:
XFS was slow on meta-data operations till 2.6.39, IIRC. Traditionally for this site you didn't mention what version of your server's kernel was. So we're only to guess now.