From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alvin Starr Subject: Re: Xen and iscsitarget Date: Thu, 04 Nov 2004 14:03:27 -0500 Message-ID: <418A7CFF.2090902@Iplink.net> References: <20041104182251.GA11808@litech.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20041104182251.GA11808@litech.org> Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: Nathan Lutchansky Cc: xen-devel@lists.sourceforge.net List-Id: xen-devel@lists.xenproject.org Nathan Lutchansky wrote: >Hi all, > >I've been using Xen for a few months now and I'm quite impressed. Not >only is the virtualization platform stable and well-designed, but the >surrounding administrative tools and processes are usable and complete. >(Although I admit, I was kind of disappointed with the performance until I >realized recently that I hadn't compiled support for my ATA chipset into >the dom0 kernel and all disk I/O was PIO.) > >My problem is that I'm unable to get the Cisco linux-iscsi initiator >running under Xen. It seems other people have been able to do this so >maybe I'm doing something wrong. > >I'm running the Xen 2.0 release candidate (which, BTW, is very nice >otherwise, I've had no other problems) and have iscsitarget 0.3.4 running >on an external host. The iscsitarget has been working fine with non-Xen >hosts. > >Unfortunately, I'm unable to get unprivileged domains to talk to the >iscsitarget. Using Linux 2.4.27-xenU with linux-iscsi 3.6.2 I get the >error "xmit_data failed to send 8240 bytes, rc 48", and using Linux >2.6.9-xenU with linux-iscsi 4.0.1.10 it simply locks up the whole kernel >on session initiation. (Pings still work though.) > >In domain 0, I can use linux-iscsi-4.0.1.10 to talk to the target >successfully, however, under load I will often get syslog messages >"iscsi-tx: page allocation failure. order:0, mode:0x20" and a big call >trace (see below). These apparently cause no real problems though, and >all my data seems to be intact and the filesystem works fine. > >Domain: Kernel: Linux-iscsi: Result: >unpriv 2.4.27-xenU 3.6.2 "xmit_data failed" >unpriv 2.6.9-xenU 4.0.1.10 immediate lock-up >domain 0 2.6.9-xen0 4.0.1.10 works fine, with strange errs > >The lock-up with 2.6.9 happens after less than a kilobyte of data has been >transmitted in either direction. > >My unprivileged domains otherwise work fine and I've pumped many >gigabytes of data between them and the network. > >Since this only breaks from an unprivileged domain, I'm guessing that >there's some incompatibility between how VIFs are implemented and how >linux-iscsi wants to use them. > >Can anybody suggest kernel and linux-iscsi versions that seem to work >correctly? -Nathan > > > I am running a Fedora Core 2 as the OS on disk for Xen0 The /proc/version string is: Linux version 2.6.8.1-xen0 (root@xenmaster1) (gcc version 3.3.3 20040412 (Red Hat Linux 3.3.3-7)) #1 Fri Oct 15 17:47:44 EDT 2004 the version of iscsi is: iscsid version 4:0.1.10 ( 8-Oct-2004) I am not saying that this is a fact but I have found that: 1) run iSCSI over gigabit ethernet only. 2) insure flow control is turned on for all the switches and NIC's 3) use only e10000 or sysconnect NIC's I have had lots of weird problems with via-rhine and 100BT connecitons. I am using the IET(iscsitarget) 0.3.2 I am importing 3 target sytemss as an array and having the XenU's do the actual raiding of them. So far So Good. Knock on wood. Keep my fingers crossed -- Alvin Starr || voice: (416)585-9971 Interlink Connectivity || fax: (416)785-3668 alvin@iplink.net || ------------------------------------------------------- This SF.Net email is sponsored by: Sybase ASE Linux Express Edition - download now for FREE LinuxWorld Reader's Choice Award Winner for best database on Linux. http://ads.osdn.com/?ad_id=5588&alloc_id=12065&op=click