> From: Bob Friesenhahn [mailto:bfrie...@simple.dallas.tx.us] > > > > But that's precisely why it's an impossible situation. In order for the > > client to see a checksum error, it must have read some corrupt data from > the > > pool storage, but the server will never allow that to happen. So the short > > answer is No. You don't need to add the redundancy at the client, unless > > you want the client to continue working (without pause) in the event the > > server is unavailable. > > I don't agree with the above. It is quite possible for the server or > network to cause an error. Computers are not error free. Network
I agree with Bob. When I said "impossible," of course that's unrealistic. But the conclusion remains the same: Redundancy is not needed at the client, because any data corruption the client could possibly see from the server would be transient and self-correcting. Out of curiosity ... Let's suppose ZFS reads some corrupt data from a device (in this case an iscsi target). Does ZFS immediately mark it as a checksum error without retrying? Or does ZFS attempt to re-read the data first? As long as a re-read is attempted, the probability of the client experiencing any checksum error at all would be very very low. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
