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