Hi list, in my case i proxy rbd to ESXi, by iSCSI fileio plugin But i see some performance problem and i can't catch where it Simple case: Ceph cluster 15 disks On proxy machine with rbd disk in FIO i see 900 IOPs 50/50 rwramdom 64 io depth Then i create iSCSI target on this RBD and connect to it, by ESXi On rbd data store, i place VM with FIO and run this test again, what i see by iostat: On VM with fio iodepth 64, latency ~700 ms on proxy machine with iSCSI and RBD: iodepth ~8 (+- 4) and latency 20-300, and i don't see any problem with CPU load May be someone already see and fix this problem, as i understand ESXi won't offload all commands to Proxy machine Scheme again: Ceph <---> rbd <---> iSCSI target <----> iSCSI Initiator <---> FIO VM FIO VM Generate load and have 64 commands in queue with crazy latency On rbd side, by iostat i see only 8 commands in queue with acceptable latency How i can debug what generate this problem in the iSCSI target <----> iSCSI Initiator Stack? And i don't observe any latency problem with ioping (i.e. if queue small enough all works perfect) Thanks -- Have a nice day, Timofey. -- To unsubscribe from this list: send the line "unsubscribe target-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
