Hi, I'm currently finding that enable WritebackThrottle lead to lower IOPS for large number of small io. Since WritebackThrottle calls fdatasync(fd) to flush an object content to disk, large number of ramdom small io always cause the WritebackThrottle to submit one or two 4k io every time. Thus, it is much slower than the global sync in FileStore::sync_entry(). Note:: here, I use xfs as the FileStore underlying filesystem. So I would know that if any impact when I disable Writeback throttles. I cannot catch the idea on the website (http://ceph.com/docs/master/dev/osd_internals/wbthrottle/). Large number of inode will cause longer time to sync, but submitting a batch of write to disk always faster than submitting few io update to the disk. Nicheal -- 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
