Date: Tue, 26 Feb 2008 13:37:09 +0100 From: Thomas Steen Rasmussen <thomas.rasmussen@ventelo.dk> To: "freebsd-scsi@freebsd.org" <freebsd-scsi@freebsd.org> Subject: iscsi initiator speed very low in FreeBSD 7 Message-ID: <4A66E92B3FBF8541A78CD11D1C0E3CFC491D952009@wp-ex02.hq.webpartner.dk>
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Gentlemen, I am experiencing some serious speed problems with the FreeBSD 7 iscsi init= iator. Introduction: We have recently purchased a SAN (EqualLogic PS5000E, I'll just refer to th= is as "SAN") to use for logfiles among other things. The SAN is accessible = through the iscsi protocol only. Windows Vista / Windows Server 2008 get impressive speeds from this SAN (20= 08 got close to 800 megabits in one test). FreeBSD is not even close to tha= t speed. I have tried a bunch of different things, but I always seem to end= up with a speed close to 700 kilobits. This is all on gigabit links. Test setup: The server (an IBM i386 blade server, EM nics, I'll call this one "blade1")= that needs to access the SAN is a production server. I have therefore configured a test-server (also some i386 blade machine, I'= ll call this one "blade2") for the sole purpose of troubleshooting this iss= ue. I do not have the resources to purchase a test SAN :), so a laptop with isc= si-target will have to do (I'll call this one "laptop-target"). The test initiator "blade2" is running FreeBSD 7.0-PRERELEASE from last wee= k, basic install with no additional stuff installed to screw it up. Iscsi-i= nitiator configured with the most basic configuration, just an target IP an= d target name. The "laptop-target" is configured with PC-BSD 1.4.1 (~FreeBSD 6.3-PRERELASE= ) and the iscsi-target port. I've been told that the iscsi-target port isn'= t built for performance, and I am keeping that in mind. Also, since it is a= laptop, the disk is unable to deliver significant amounts of data. But I b= elieve this test still remains valid. For the test there is a crossover cable between "blade2" and "laptop-target= ", they are both configured with private static IP addresses and the connec= tivity between them is fine. Iperf got to around 690 megabits in a quick te= st. A real world test with SCP also achieved OK speed. I mount the iscsi-ta= rget and try to copy something to the iscsi mounted directory. It works but= the speed is still around 700 kilobits. To make sure this isn't a problem where my test "laptop-target" is unable t= o deliver enough data for some reason, I tried mounting the same target fro= m Windows Vista, formatted it and tested the speed, it got to around 130 me= gabit which I believe is around the max limit for the poor 5400 rpm laptop = drive. So no problems with the laptop, no problems with iscsi-target. The p= roblem really seems to be with the FreeBSD iscsi initiator. I've reproduced this same result again and again and I fail to see any comm= on points between the two separate cases where I have the problem. My netwo= rk or the SAN certainly can't be blamed after seeing the results of this te= st, using a crossover cable and alternate iscsi target. After mailing a bit with Danny Braniss I learned that he got his initiator = to deliver in excess of 80 megabytes/sec when the target is a dedicated app= liance, and 50 megabytes/sec when the target is the iscsi-target port. Nice= to hear that the initiator code is solid enough to deliver speeds like tha= t, but why on earth doesn't it work for me ? dmesg, configs etc. will be forwarded immediately upon request if necessary= :) Thank you in advance! Med venlig hilsen/Kind regards Thomas Rasmussen Sikkerheds- og Unix-Administrator Ventelo Direkte: + 45 35 25 47 46| Mobil: + 45 27 80 80 90 Tlf.: + 45 70 26 23 00 | Fax: + 45 70 26 23 01 =C5rhusgade 88, 2100 K=F8benhavn =D8 thomas.rasmussen@ventelo.dk | www.ventelo.dk
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