On Mon, May 1, 2017 at 9:17 AM, Babu Shanmugam <babu@xxxxxxxx> wrote: > > My intention is to just identify the root cause for the too much time spent on a "table create" operation on CephFS. I am *not* trying to benchmark with my testing. Sorry if it wasn't clear in my mail. > > I am sure the time spent would be lesser if I had a proper CEPH setup. But, I believe even then, the "Table create" operation takes more time in CephFS than RBD. Please correct me if I am wrong. As your data shows, fsync is just much slower on CephFS. I think you'd find the difference was less on a real cluster, but it's always going to be slower than RBD is — an fsync requires committing metadata updates, and that requires the client sending a message to the MDS which then commits to RADOS, PLUS the client sending out its own data directly to RADOS. In comparison, RBD is just talking to OSDs directly, and often enough an fsync will only require one message (or more commonly two in parallel?) so it's going to perform better no matter how much stuff gets optimized. *shrug* -Greg _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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