KVM Forum 2014

The discussion is around KVM disk I/O performance + latency using different approaches including vhost-scsi + in-kernel target, QEMU virtio-scsi, and virtio-blk/data-plane. This includes current developments for scsi-mq, and benefits that a blk-mq based I/O stack brings to the virtio-scsi LLD. It also covers remaining TODOs for supporting live migration in vhost-scsi code, and extra considerations with in-kernel LIO target state like SPC-3 persistent reservations and ALUA port access state across multiple nodes utilizing shared storage. Other topics include vhost-scsi support in Openstack, guest support for T10 Protection Information (PI), DIF metadata for application tagging of individual in-guest storage blocks, and different use cases for vhost-scsi vs. virtio-scsi dataplane + user-space iSCSI initiator.