+++ /dev/null
-========================
- Differences from POSIX
-========================
-
-.. todo:: delete http://ceph.com/wiki/Differences_from_POSIX
-
-Ceph does have a few places where it diverges from strict POSIX semantics for various reasons:
-
-- Sparse files propagate incorrectly to tools like df. They will only
- use up the required space, but in df will increase the "used" space
- by the full file size. We do this because actually keeping track of
- the space a large, sparse file uses is very expensive.
-- In shared simultaneous writer situations, a write that crosses
- object boundaries is not necessarily atomic. This means that you
- could have writer A write "aa|aa" and writer B write "bb|bb"
- simultaneously (where | is the object boundary), and end up with
- "aa|bb" rather than the proper "aa|aa" or "bb|bb".