Filesystem creation and checking time
The first test is related to filesystem creation and checking time. The following graph will show you the time needed to create and fsck the ~10 TB filesystem used to fill the RAID 10 array. The fsck command was run after the creation of a significant number of small file, obtained unpacking the linux-126.96.36.199.tar.bz2 file downloaded form kernel.org:
As you can see, XFS was way faster then EXT4 in this large volume creation and checking. However, you should not overestimate these results: remember that you generally create the FS only one time, and the fsck operation should be a rare one (after all, both FS are journaled for this reason). On the other hand, if you plan to create/check very ofter a large filesystem, stay away from EXT4 and go with XFS.