Try setting some queue depth, like 64. Not sure what FIO defaults to if not specified but if it is 1 that won't yield good performance.
-------- Original message -------- From: Wyllys Ingersoll Date:08/25/2014 3:49 PM (GMT-08:00) To: open-iscsi@googlegroups.com Subject: Re: iscsi over RBD performance tips? Yes, using open-iscsi with tgt as the target side. I used fio with the following job file. I only used 1 job (thread) because I want to see the max that a single job can read at a time. Even by maximizing the MaxXmitDataSegmentLength and MaxRecvDataSegmentLength, I dont see much difference. [default] rw=randread size=20g bs=16m ioengine=libaio direct=1 numjobs=1 filename=/dev/sdb runtime=600 write_bw_log=iscsiread Then I ran fio as follows: $ fio iscsi.job On Friday, August 22, 2014 5:00:33 PM UTC-4, Mike Christie wrote: Are you using linux for the initiator? If so, what is the throughput you get from just using this open-iscsi initiator connected to tgt with a ram disk? I just installed RBD here for work, so let me check it out. What io tool are using and if it is something like fio could you post the arguments you used to run it? On Aug 21, 2014, at 4:10 PM, Wyllys Ingersoll <wyl...@gmail.com> wrote: Im looking for suggestions about maximizing performance when using an RBD backend (Ceph) over a 10GB Ethernet link. In my testing, I see the read throughput max out at about 100Mbyte/second for just about any block sizes above 4K (below 4K it becomes horribly slow) and write operations are about 40Mbyte/second. Using librados directly to read from the same backend pool/image yields much higher numbers, so the issue seems to be in the iscsi/bs_rbd backend. Regardless of the data sizes being read, the max thruput I am seeing is about 80% slower than using librados directly. Any suggestions would be much appreciated. thanks, Wyllys -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+...@googlegroups.com. To post to this group, send email to open-...@googlegroups.com. Visit this group at http://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com<mailto:open-iscsi+unsubscr...@googlegroups.com>. To post to this group, send email to open-iscsi@googlegroups.com<mailto:open-iscsi@googlegroups.com>. Visit this group at http://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To unsubscribe from this group and stop receiving emails from it, send an email to open-iscsi+unsubscr...@googlegroups.com. To post to this group, send email to open-iscsi@googlegroups.com. Visit this group at http://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout.
