Re: iSCSI problems

[Alvin Starr <alvin@iplink.net>]

Edwards, Nigel (Nigel Edwards) wrote:

>Hi,
>I am having problems getting iSCSI working with xen. I can access
>iSCSI drives fine from Xen0 (e.g. untar a 500MB archive and I don't
>see problems reported through dmesg or /proc/kmsg). However, if I try
>to project them into an instance of XenU as a scsi device to boot the
>unprivileged domain I get an oops in Xen0 - often resulting in the
>whole machine crashing.  This occurs in the very early stages of boot
>of xenU.
>
>I am using linux-iscsi-4.0.2 for iscsi_sfnet.ko
>scsi_transport_iscsi.ko is being built in linux-2.6.12-xen0
>I downloaded xen-unstable-src.tgz October 25th.
>
>I notice that there appear to be some significant differences between
>scsi_transport_iscsi.c in linux-iscsi-4.0.2 and the version in 
>linux-2.6.12 kernel.
>
>Example oops below. I have also attached the domain config file. I am
>not sure what to do next to get this working.  Any suggestions would
>be appreciated. If you have iSCSI working, if you could drop me a note
>indicating what code and modules you are using I would be very grateful.
>
>Cheers,
>Nigel.
>  
>
Having played with this I would suggest that you use iSCSI in Dom0 and 
export the disks from Dom0 to the varios DomU's.
I have managed to get this working with the aid of some hacks to the 
UDEV configuration files so that I can get a deivce entry like 
/dev/magical-iscsi-targetname.my.fun.domain.com.
It is then easy to map these things into the approprate DomU configs.

I would be concerned about using iSCSI in the DomU's because of the 
extra network overhead in propigating the data across the bridge.

-- 
Alvin Starr                   ||   voice: (416)585-9971
Interlink Connectivity        ||   fax:   (416)585-9974
alvin@iplink.net              ||