I follow state of iSCSI and FCoE on linux since a few years ago. But ... It seems slow and Wrong Way !
Altough kernel SCSI maintainer like the move everyting to userspace idea. But it not good for performance. I know that SCST already exists and mature but not going to mainline kernel. Why ? because kernel maintainer doesn't like this way and more likely happy to have STGT instead (which use much userspace things).
I tried both but STGT performance is simply BAD!. Like iSCSI, moving to more complicated layers to handle such storage low-lattency things is BAD!. So, by the same reason, iSCSI not so popular on performance storage because of too much overhead added to processing and it increasing lattency, although throughput seems ok (1GBPS with only 2-3% cpu load even on software initiator) but SCST proves to have lower lattency very close to pure HW implemantation. but STGT is more likely to have delay on userspace processing.
Something wrong ? Although STGT is more good, but SCST is mature enough to get it to mainline kernel for now. It should be, at least, for everyone to test on the mainlike kernel both SCST and STGT to see what is good for real life usage.
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