[lsattr flag] T [chattr option] +T to set -T to clear [Semantics and rationale] A directory with the T attribute will be deemed to be the top of directory hierarchies for the purposes of the Orlov block allocator. This is a hint to the block allocator used by ext3 and ext4 that the subdirectories under this directory are not related, and thus should be spread apart for allocation purposes. For example: it is a very good idea to set the T attribute on the /home directory, so that /home/john and /home/mary are placed into separate block groups. For directories where this attribute is not set, the Orlov block allocator will try to group subdirectories closer together where possible. [Attribute] 
Top of directory hierarchy