On Tue, Apr 20, 2010 at 02:46:35AM +0100, Jamie Lokier wrote: > Does this mean that virtio-blk supports all three combinations? > > 1. FLUSH that isn't a barrier > 2. FLUSH that is also a barrier > 3. Barrier that is not a flush > > 1 is good for fsync-like operations; > 2 is good for journalling-like ordered operations. > 3 sounds like it doesn't mean a lot as the host cache provides no > guarantees and has no ordering facility that can be used. No. The Linux virtio_blk guest driver either supports data integrity by using FLUSH or can send down BARRIER requests which aren't much help at all. Qemu only implements FLUSH anyway. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
