On Aug 22, 2014, at 12:07 PM, Redwood Hyd <redwood...@gmail.com> wrote:
> Hi All, > I am trying to achieve10Gbps in my single initiator/single target env. > (open-iscsi and IET) > > I exported 3 Ramdisks, via 3 different IP aliases to initator, did three > iscsi logins , 3 mounts points and then 3 fio jobs in parallel (256K block > size each). > > Question 1) Is above a real use case where from same iscsi initiator i did 3 > iscsi logins to same target (via different IP addresses) ? Anything pros/cons > with this. This seems normal. > > Question 2) What are the other best ways to create parallel TCP flows > (because it seems open-iscsi does'nt have MC/S support) Multiple sessions to different portals then use dm-multipath over all those paths/sessions to the LU. > Question 3) In this scenario can I use dm-multipath - can someone suggest > most common way so that at TCP level i get multiple flows. > What you described above, when you run /sbin/multipath /sbin/multipath -ll Do you see each device having 3 paths? Did you set it up to do round robin for dm multipath path selection? If so, each path is going to be a different tcp socket connection which the iscsi initiator and dm-multipath will use to send IO on. At my last job, fusion-io/sandisk, we sold a high performance target, and to get the highest throughput when using linux we had to create extra sessions/connections to avoid some bottlenecks in the linux block/scsi layer. Above you would have a session to each target portal/ip. We would set node.session.nr_sessions in iscsid.conf to greater than one so each portal would have nr_sessions sessions/connections. When you run iscsiadm -m node -T target -p ip -l, iscsiadm would then create nr_session to that portal. iscsiadm -m session would show the extra sessions when logged in and multipath -ll should show the extra paths. You can also just do iscsiadm -m session -R SID -o new to dynamically add another session/connection. -- 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 firstname.lastname@example.org. Visit this group at http://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout.