>>>>> "kth" == Kjetil Torgrim Homme <kjeti...@linpro.no> writes:
kth> basically iSCSI just defines a reliable channel for SCSI. pft. AIUI a lot of the complexity in real stacks is ancient protocol arcania for supporting multiple initiators and TCQ regardless of whther the physical target supports these things, multiple paths between a single target,initiator pair, and their weird SCTP-like notion that several physical SCSI targets ought to be combined into multiple LUN's of a single virtual iSCSI target. I think the mapping from iSCSI to SCSI is not usually very direct. I have not dug into it though. kth> the SCSI layer handles the replaying of operations after a kth> reboot or connection failure. how? I do not think it is handled by SCSI layers, not for SAS nor iSCSI. Also, remember a write command that goes into the write cache is a SCSI command that's succeeded, even though it's not actually on disk for sure unless you can complete a sync cache command successfully and do so with no errors nor ``protocol events'' in the gap between the successful write and the successful sync. A facility to replay failed commands won't help because when a drive with write cache on reboots, successful writes are rolled back.
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