A couple of releases ago, ceph has changed the default value for rbd cache writethrough until flush from false to true. As the fio rbd backend currently does not emit the necessary fsync to trigger writeback mode, this implies that tests will run in writethrough, possibly giving a significantly reduced performance when compared to other clients, e.g. when running fio within a qemu-based instance accessing the same RBD volume. Would it make sense for fio to simply issue a rbd_flush after each rbd_open at https://github.com/axboe/fio/blob/master/engines/rbd.c#L138 ? Or do you think that this would need a dedicated flag to be enabled? -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
