On 23/09/2013 18:59, Gregory Farnum wrote: > On Mon, Sep 23, 2013 at 1:34 AM, Loic Dachary <[email protected]> wrote: >> Hi, >> >> Unless I'm mistaken, ceph_crc32() is currently used in master via the >> crc32c() method of bufferlist to: >> >> * encode_with_checksum/decode_with_checksum a PGLog entry >> * Message::decode_message/Message::encode_message a message via calc_*_crc >> * FileJournal::do_read_entry/FileJournal::prepare_single_write a journal >> entry >> * for information in the report monitory command ( Monitor.cc ) >> >> Erasure coded chunks ( i.e. files ) will need checksums. Should this be >> implemented as an optional feature in ceph/src/os/FileStore.{h,cc} ? If the >> underlying filesystem does not provide this feature, FileStore would call >> ceph_crc32 each time the object is modified. A verification method would be >> exposed and used when scrubbing erasure coded pools. > > You mean should checksums be optional in the FileStore, or should we > provide a plugin framework for using things other than crc32, or...? > :)
Not really. I was under the impression that crc32 is good enough. I'm not sure where ( in the code path ) it should be used for erasure coded pools. In the FileStore ? Or in the erasure code PG to set an attribute of the object ? The FileStore seems to be more sensible but ... I'm not sure hence the mail ;-) > -Greg > Software Engineer #42 @ http://inktank.com | http://ceph.com > -- Loïc Dachary, Artisan Logiciel Libre All that is necessary for the triumph of evil is that good people do nothing.
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