mirror of
https://github.com/ceph/ceph
synced 2024-12-12 14:39:05 +00:00
18 lines
815 B
ReStructuredText
18 lines
815 B
ReStructuredText
========================
|
|
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".
|