mirror of
https://github.com/ceph/ceph
synced 2024-12-22 19:34:30 +00:00
17 lines
754 B
ReStructuredText
17 lines
754 B
ReStructuredText
|
========================
|
||
|
|
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".
|