Ric Wheeler wrote:
Thing is being pitched to answer a very specific customer use case - shared storage (mid to high end almost exclusively) with several different users and applications....
And by "different users" these customers almost always mean different operating systems. They are combining storage into a central location for easier management. So "exact unmapped tracking by the filesystem" is impossible and not part of the requirement. Doesn't mean we can't make our filesystems better, but forget about a perfect ability to known just how much space we really have once we do an unmap. We can't tell how much of our unmapped space the device has given away to someone else and we cannot prevent the device from failing a write to an unmapped block if all the space is gone. It is just an IO error, and possible fs-is-offline if that block we failed was metadata! It is up to the customer to manage their storage so it never reaches the unable-to-write state. jim -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
