[PVE-User] ISCSI - which target software?

[Stefan Sänger]

Hi together,

I am using proxmox for quite some time, but finally encountered a 
problem that is rather strange...

When I have been using iscsi so far it was either done by using a 
reasonable prices appliance (e.g. Thecus or QNAP) or quite a while ago 
openfiler.

Since openfiler is discontinued I thought about using LIO and ran into 
the same problem as described in this forum post:

http://forum.proxmox.com/threads/13759-iSCSI-errors-on-storage-server

My setup:

- storage is a wheezy system, running debian 3.2. kernel
- a configured and running 5-node-cluster made up of some older
   stand-alone servers and 3 IBM blades
- current version of proxmox, uname -a says:
   Linux pve04 2.6.32-29-pve #1 SMP Thu Apr 24 10:03:02 CEST 2014 x86_64


I installed the storage server, configured iscsi using targetcli,
attached it to proxmox cluster, created a volume group and started to 
migrate some virtual harddisks to the new storage.

After moving some disks succesfully (and having the VMs up and running 
again) migration failed.

Log at storrage shows:

May 19 11:43:45 dellstor kernel: [176461.892165] rx_data() returned an 
error.
May 19 11:43:45 dellstor kernel: [176461.892194] iSCSI Login negotiation 
failed.

These two lines appeared every 2 to 6 seconds.

I figured that there may be a problem in lio modules, and tried to 
upgrade to a later kernel. Unfortunately wheezy-backports only offer a 
very recent kernel, but iscsitarget-dkms is broken for using debian 
stable with backport kernel.

Anyway - I then got messages like:

May 19 11:55:52 dellstor kernel: [   97.840090] iSCSI Login negotiation 
failed.
May 19 11:55:52 dellstor kernel: [   97.840175] rx_data returned 0, 
expecting 48.

So, downgraded kernel again and with some hassle I was able to move all 
the migrated disks back.


So now the question for me is pretty simple: Am I going to go back to 
using iet, should I try stgt or perhaps just a working combination of 
recent lio-utils / iscsitarget / iscsitarget-dkms?

I may try to install ubuntu trusty istead of wheezy on the storage 
server. But I would like to learn what iSCSI implementation you guys are 
using and if you see any other pitfalls...


Best regards,

Stefan