Re: iscsi-target problem with VirtualBox initiator

[Dan Nelson <dnelson%allantgroup.com@localhost>]

In the last episode (Oct 30), Daniel Carosone said:
> On Wed, Oct 29, 2008 at 05:58:00PM -0500, Dan Nelson wrote:
> > My patches work (and don't break either the Windows or Solaris
> > native initiators' ability to connect), but my guess is that
> > there's a more-correct fix.
> 
> Aside from your real question... How much success have you had with
> the opensolaris initiator to the netbsd target? 

I'm just running s10u5 on my test box at the moment.
 
> The connection falls over for me under load (such as when trying to
> copy any real volume of data into the zfs pool built on the target
> disks). It's a known issue to do with multiple threads from the
> initiator. 

I get pretty frequent warnings from the kernel of the form

WARNING: iscsi connection(72) protocol error - received status out of order 
itt:0x192 statsn:0xcc expstatsn:0xcd

(both with and without my patches), and the initiator drops and
reconnects. Copying large files onto a zfs filesystem goes at wire
speed (only 100mbit link here though) for a few seconds, then I get a
flood of those "out of order" messages followed by a couple of these:

scsi: [ID 107833 kern.warning] WARNING: 
/iscsi/disk%0000iqn.1994-04.org.netbsd.iscsi-target@localhost%3Atarget20001,0 
(sd32):
      SCSI transport failed: reason 'tran_err': giving up

and the connection goes idle for a couple seconds, followed by the
Solaris box panicing because it couldn't write to the pool (opensolaris
and zpool failmode=continue would have saved me here).  Reading the
written data after a reboot gives me wire-speed for about 10 seconds,
then I get an "out of order" kernel warning, and read speed drops to
~140KB/sec with no more warnings.  This may be the Solaris initiator
falling back to some paranoid-safe mode; I haven't compared packet
dumps to see what changes.
 
> I had considered trying the virtualbox initiator as a workaround but
> hadn't gotten around to it yet.. (I have an opensolaris virtualbox
> test instance too, which is updating right now, entirely
> coincidentally..)

The virtualbox initiator seems to play very well with iscsi-target.  My
main reason for trying it is that we recently got hugely overpowered
Core2-Quad 4GB desktop machines and I want to put mine to work doing
more than running a screensaver :)

-- 
        Dan Nelson
        dnelson%allantgroup.com@localhost