Hello KS-2012 PCs, I would like to attend KS-2012 this year in San Diego, and think I can benefit the discussion in the following ways.. I'm maintainer of the target storage subsystem merged in .38 code using the first fabric independent inter-module configfs control plane. With lots of help of target developers (hch, agrover, hannes), other subsystem maintainers (roland, greg-kh, james, felipe, stefan), and new devels (bart, bootc, sebastian) the team has manage to merge seven fabric drivers, including three new drivers this round for v3.5 code (usb-gadget, sbp-target, tcm_qla2xxx). For the 3.6 -> 3.7 time frame, one of the bigger items still on the TODO list is how collectively the scsi <-> target subsystems are going to be able to support "hot" target/initiator mixed-mode operation. There has been some discussion on this topic on linux-scsi + target-devel, but we've not decided on a path forward here yet.. Also, another important topic for scsi that will need to eventually be addressed is the per-lun performance limitations / bottleneck currently present with v3.x Linux/SCSI clients for random small block IOPs workloads. Even after SCSI tree wide host-lock less conversion starting in .38 code, Linux/SCSI client LUNs (regardless of fabric / LLD) are still well behind what a raw block client is capable for 1 million IOPs machine. The Linux/SCSI client is also behind (on the order of ~25%) of what certain non Linux client can achieve connected to the same Linux target using raw block backends in an apples-to-apples comparison. Finally on the new target fabric driver front, we're currently expecting the tcm_vhost driver to be a merge candidate in the v3.6 -> v3.6 time frame. This driver provides high performance backend (pSCSI, IBLOCK, FILEIO) device access using existing vhost infrastructure for connecting para-virtualized virtio-scsi guest code directly to the in-kernel target infrastructure. This is some really pretty exciting code, and I'll be sending time on virto-scsi <-> tcm_vhost performance profiling using raw block flash backends to get a rough idea of where things currently stand.. Also by the time KS/LC comes around in August, we expect to have the first shared-storage host virtualized ALUA multipath prototype up and running on mainline target code.. Thank you! --nab -- 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
