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http://blogs.sun.com/dweibel/date/20051021 Friday October 21, 2005

Storage Networking World - Fall 2005



If your in Orlando at SNW this week. Come take a peek at Sun's
Solaris 10 iSCSI initiator at the 2005 Fall Storage Networking World!



Storage Networking World
October 24 - 27, 2005
JW Marriott Grande Lakes Resort
Orlando, FL
http://www.snwusa.com/

http://blogs.sun.com/dweibel/date/20051014 Friday October 14, 2005

Request: iSCSI Target Vendors - Solaris iSNS client support

Sun is working hard to implement iSNS client support for the Solaris iSCSI initiator in the near future. In preparation for this support our team has spent allot of time testing with different vendors hardware. Our development team has an interop lab containing hardware from most major iSCSI vendors. So this request is more for some of the smaller iSCSI vendors in the market space.


We have seen a couple issues with vendor implementations around iSNS. Those vendors have been notified and are working to resolve any issues with their devices. Again this request is really targeted to the vendors that we don't have hardware or time to test. For you we have a couple easy checks you can perform to verify your devices are going to work with the Solaris initiator's iSNS support.


Step 1.
Ensure your target can properly register with Microsoft's 3.0 iSNS server. (Yes, I said Microsoft. They have a good reference implementation of an iSNS server that is available for free, Today.)
Step 2.
When registering with the iSNS server make sure you are properly representing your portal groups. Specifically the PG Tag. This iSNS PG Tag should represent the same value received during an iSCSI full feature login for the TargetPortalGroupTag. If not our initiator will not trust the data you are returning and will fail the login.

We have seen two gotchas in this area with some vendor implementations

Gotcha 1.
If you don't register a PG Tag you are assigned a default PG Tag of 1 (RFC 4171 Section 6.5.4). In this case you must return a TargetPortalGroupTag of 1 during the iSCSI full feature login.
Gotcha 2.
Be careful in the ordering of your keys in your iSNS registration. If ordered wrong your PG Tag may be ignored by the iSNS server. As an example if you think you register PG Tag 5. I recommend you actually snoop/ethereal a trace of the value the iSNS server is returning to the initiator. It may have ignored the incorrect ordering of your keys and you also will gain the default PGTag of 1 causing the initiator to fail the login.

If you verify these two checks with you implementation you should be safe. In addition we hope to make our iSNS client support available via Solaris Express in the next couple months and recommend you test with our initiator.


Solaris Express packages on S10

A number of people in the field have been applying Solaris Express (nevada) packages against Solaris 10 to get iSCSI. I don't think this is officially supported by Sun? I'm still trying to figure that out. Most people doing this are hitting the following problem on sparc.

WARNING: iscsi driver unable to online iqn.1986-03.com.sun:01:00093d12170c.434c5250.vol0 lun 0

What this really means is the associated target driver is not configured or is failing its attach(). Those sneaky customers out there applying express packages against S10 will see this 100% of the time on sparc. The problem is not with the iSCSI software. Your missing a /etc/driver_aliases entry. You need to ensure you have the following driver_alias entry to cause the iSCSI logical unit to bind to the target driver. This entry states that a class scsi device with INQUIRY Device Type of 00 (Disk) should bind to the target driver sd (Disk Driver).

sd "scsiclass,00"

You can find more details on driver_aliases in its manpage.

If you apply a full Solaris Nevada install or use official S10 patches to get iSCSI this will not occur. We add the entry for you. As a final note, Beware stability levels are different between Solaris Express and official S10 patches. Solaris Express is the bleeding edge, similar to downloading code from opensolaris.org building it and installing it on your machine.


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