Hi, Gregory! Thanks for the comment. I compiled simple program to play with write speed measurements (from librados examples). Underline "write" functions are: rados_write(io, "hw", read_res, 1048576, i*1048576); rados_aio_write(io, "foo", comp, read_res, 1048576, i*1048576);
So I consecutively put 1MB blocks on CEPH. What I measured is that rados_aio_write gives me about 5 times the speed of rados_write. I make 128 consecutive writes in for loop to create object of maximum allowed size of 132MB. Now if I do consecutive write from some client into CEPH storage, then what is the recommended buffer size? (I'm trying to debug very poor Bareos write speed of just 3MB/s to CEPH) Thank you, Alexander On Fri, Sep 29, 2017 at 5:18 PM, Gregory Farnum <gfar...@redhat.com> wrote: > It sounds like you are doing synchronous reads of small objects here. In > that case you are dominated by the per-op already rather than the > throughout of your cluster. Using aio or multiple threads will let you > parallelism requests. > -Greg > On Fri, Sep 29, 2017 at 3:33 AM Alexander Kushnirenko < > kushnire...@gmail.com> wrote: > >> Hello, >> >> We see very poor performance when reading/writing rados objects. The >> speed is only 3-4MB/sec, compared to 95MB rados benchmarking. >> >> When you look on underline code it uses librados and linradosstripper >> libraries (both have poor performance) and the code uses rados_read and >> rados_write functions. If you look on examples they recommend >> rados_aio_read/write. >> >> Could this be the reason for poor performance? >> >> Thank you, >> Alexander. >> _______________________________________________ >> ceph-users mailing list >> ceph-users@lists.ceph.com >> http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com >> >
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