OpenSolaris 2009-06 and the Comstar iScsi Target

Having upgraded from OpenSolaris 2008-11 to 2009-06, I wanted to try the new Comstar iscsi target, to see how well it worked, and to see if it was ready to replace the 'old' iscsi target. And I wanted to see how far I could get with the package versions in the 'production-quality' release repository, based on snv_111. To start with, I just wanted to get something basic going as quickly as possible.

The first tasks was to disable the old iscsi target (to avoid a conflict with the new target which would also want to listen on TCP port 3260), and to enable the 'SCSI Target Mode Framework' - stmf.

# svcs iscsitgt
online         Jul_09   svc:/system/iscsitgt:default
# svcs stmf
disabled       Jul_09   svc:/system/stmf:default
# svcadm disable iscsitgt
# svcs iscsitgt
STATE          STIME    FMRI
disabled       21:29:57 svc:/system/iscsitgt:default
# svcadm enable stmf
# svcs stmf
STATE          STIME    FMRI
online         21:30:55 svc:/system/stmf:default
# stmfadm list-state
Operational Status: online
Config Status     : initialized

Next I created a new small zfs volume.
(My zfs pool is named 'rz2pool' - it's Raidz2 - dual parity.)

# zfs create -V 4g rz2pool/iscsi_lun1

And then created a 'logical unit', using the zvol as it's backing store.

# sbdadm create-lu /dev/zvol/rdsk/rz2pool/iscsi_lun1

Created the following LU:

             GUID                    DATA SIZE           SOURCE
--------------------------------  -------------------  ----------------
600144f00008278f04694a5cf0980001      4294901760       /dev/zvol/rdsk/rz2pool/iscsi_lun1

# stmfadm list-lu -v
LU Name: 600144F00008278F04694A5CF0980001
   Operational Status: Online
   Provider Name     : sbd
   Alias             : /dev/zvol/rdsk/rz2pool/iscsi_lun1
   View Entry Count  : 0

Now using the GUID of the logical unit, we make it visible to any initiators, by adding a 'view'

# stmfadm add-view 600144f00008278f04694a5cf0980001
# stmfadm list-view -l 600144f00008278f04694a5cf0980001
View Entry: 0
   Host group   : All
   Target group : All
   LUN          : 0

Next we need to do the iscsi part, for which we need to install the iscsi target and the 'itadm' command. These were not already installed so I had to add the 'SUNWiscsit' package.

# pkg install -v SUNWiscsit
Creating Plan | Before evaluation:
UNEVALUATED:
+pkg:/SUNWiscsit@0.5.11,5.11-0.111:20090508T161047Z

After evaluation:
None -> pkg:/SUNWiscsit@0.5.11,5.11-0.111:20090508T161047Z
None -> pkg:/SUNWiscsidm@0.5.11,5.11-0.111:20090508T161041Z
Actuators:
     restart_fmri: svc:/system/manifest-import:default
None
DOWNLOAD                                    PKGS       FILES     XFER (MB)
Completed                                    2/2       23/23     0.66/0.66

PHASE                                        ACTIONS
Install Phase                                  76/76
PHASE                                          ITEMS
Reading Existing Index                           8/8
Indexing Packages                                2/2

# pkg list -v SUNWiscsit
FMRI                                                             STATE      UFIX
pkg:/SUNWiscsit@0.5.11,5.11-0.111:20090508T161047Z               installed  ----
# pkg list -v SUNWiscsidm
FMRI                                                             STATE      UFIX
pkg:/SUNWiscsidm@0.5.11,5.11-0.111:20090508T161041Z              installed  ----

On the next step I had a small problem.
(BTW, I am not using NWAM to configure my network card.)

# svcadm enable -r iscsi/target:default
svcadm: svc:/milestone/network depends on svc:/network/physical, which has multiple instances.

# svcs -a | grep network/physical
disabled       Jul_09   svc:/network/physical:nwam
online         Jul_09   svc:/network/physical:default

# svcadm enable  iscsi/target
# svcs -a | grep iscsi
disabled       Jul_09   svc:/network/iscsi_initiator:default
disabled       21:29:57 svc:/system/iscsitgt:default
maintenance    22:29:13 svc:/network/iscsi/target:default

# svcs -xv
svc:/network/iscsi/target:default (iscsi target)
State: maintenance since Tue Jul 14 22:29:13 2009
Reason: Start method failed repeatedly, last exited with status 4.
  See: http://sun.com/msg/SMF-8000-KS
  See: man -M /usr/share/man -s 1M itadm
  See: /var/svc/log/network-iscsi-target:default.log
Impact: This service is not running.

# tail /var/svc/log/network-iscsi-target\:default.log
[ Jul 14 22:29:13 Enabled. ]
[ Jul 14 22:29:13 Executing start method ("/lib/svc/method/iscsi-target start"). ]
iscsi-target: Requesting to enable iscsi target
open failed: INVALIDUnable to open device /devices/pseudo/iscsit@0:iscsit[ Jul 14 22:29:13 Method "start" exited with status 4. ]

Rebooting solved this problem.

# svcs -a | grep iscsi
disabled       19:25:15 svc:/network/iscsi_initiator:default
disabled       19:25:18 svc:/system/iscsitgt:default
online         19:25:37 svc:/network/iscsi/target:default

So now we create the iscsi target and check it looks ok:

# itadm create-target
Target iqn.1986-03.com.sun:02:7e969860-cb8d-475a-ddbb-97bf2f22ce7b successfully created

# itadm list-target -v
TARGET NAME                                                  STATE    SESSIONS
iqn.1986-03.com.sun:02:7e969860-cb8d-475a-ddbb-97bf2f22ce7b  online   0
       alias:                  -
       auth:                   none (defaults)
       targetchapuser:         -
       targetchapsecret:       unset
       tpg-tags:               default

I was then able to discover and logon to this iscsi target from a Windows 2003 server, using the Microsoft iscsi initiator.

The above is just the simplest possible configuration, just to allow some simple tests. For a more practical setup, you may well want multiple logical units, and want to put some restrictions on the views. But details on how to do that will have to wait for a follow-up post to this blog!

I did notice a couple of things fairly quickly. I saw the connection between the initiator and target was dropping every 50 seconds, followed immediately by a re-logon. Checking with WireShark showed that it was the target starting this with a [FIN, ACK]. With the old iscsi target I would have used DTrace to confirm this, but the iscsi target provider for the new iscsi target was not available.

I looked at the source code for the comstar iscsi target:

http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/io/comstar/port/iscsit/iscsit.c

.. and from the history link, I could see that a couple of likely fixes had already been committed:

26-May-2009 Priya Krishnan - 6809997 COMSTAR iscsi target DTrace Provider needed
08-May-2009 Peter Dunlap - 6755803 win2003 initiator numerous iscsi connection lost and connection retries mesgs to iscsi target

Now normally, I would hyper-link those bug number for you. But in this case there is no point, because Sun has chosen not to allows details of those bugs to be publicly available. (Or any of the other comstar iscsi target bugs AFAIK.)

Having those fixes is important for me, so it looks like I will have to update my OpenSolaris 2009-06 using the development repository to snv_118.