On Wednesday, June 27, 2018 at 12:34:56 PM UTC-7, Neutron Sharc wrote: > > Hi all, > > I will describe the problem I saw step by step. Please take patience. > > I'm using tgt as iscsi target server (fujita/tgt from github) on Ubuntu > 16.04. iscsi initiator runs the stock open-iscsi coming with Ubuntu 16.04. > > The default "/etc/iscsi/iscsid.conf" defines "node.session.queue_depth = > 32". I changed it to 128, and run "sudo iscsid restart". Then I log in to > an iscsi target. > > However, " iscsiadm -m node -p xxx -T yyy" shows my iscsi session still > uses "queue_depth" as 32, not 128. > > Then I run "iscsiadm -m node -p xxx -T yyy --op update -n > node.session.queue_depth -v 128" to forcefully change the value. > > This time "iscsiadm -m node" shows the correct "128" value I set. > > Now I run fio benchmark with a large queue size (1024), and keeps > monitoring iscsi target. I had a patch in tgt to report the current live > commands received on a connection. > To my surprise, this max "queued_cmd" is always 32, not 128, no matter > how hard I push fio queue size. > > I was expecting that, since I set initiator session.queue_depth to 128, > the target should receive a max 128 cmds in its queue. > > I want the initiator to push as many requests as possible to target to get > more bandwidth. However the target only receives up to 32 outstanding cmds > from initiator. Why doesn't initiator push more? > > Is my understanding about "node.session.queue_depth" correct? > > > > -Shawn > > > I _believe_ that queue_depth, in this context, ralates to the cmdsn (command sequence number) window that the iscsi transport will allow, i.e. how many iSCSI commands can be active at one time? But that's from a really quick glance at the code.
Also, as far as setting it in iscsid.conf, that doesn't effect any current node records. You can change the node "queue_depth" value using "iscsiadm -m node ... --name node.session.queue_depth --value SOME_NUMBER" -- 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 https://groups.google.com/group/open-iscsi. For more options, visit https://groups.google.com/d/optout.
