> nexenta - libiscsi: > -------------------- > default: 4000 (some hangs) > cache=none : 14000 > cache=writeback : 5000 (some hangs) I do not really understand that. The qemu iscsi.c driver ignore the BDRV_O_NOCACHE flag, so how can this result in any difference?! see qemu-kvm/block/iscsi.c