On Mon, Sep 23, 2013 at 8:18 PM, Sage Weil <sage@xxxxxxxxxxx> wrote: > You > might try measuring that directly and comparing it to the 33ms > append+fsync that you previously saw. dd with fsync is quite slow... [root@p05151113777233 fio]# time dd if=/dev/zero of=/var/lib/ceph/osd/osd.1045/testtest bs=5 count=1 1+0 records in 1+0 records out 5 bytes (5 B) copied, 8.884e-05 s, 56.3 kB/s real 0m0.001s user 0m0.000s sys 0m0.001s [root@p05151113777233 fio]# time dd if=/dev/zero of=/var/lib/ceph/osd/osd.1045/testtest bs=5 count=1 conv=fsync 1+0 records in 1+0 records out 5 bytes (5 B) copied, 0.0435103 s, 0.1 kB/s real 0m0.045s user 0m0.001s sys 0m0.001s -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
