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New Member

scsi device discovery in Cisco MDS switches

I was using this device discovery to find out how many luns can be seen on that server.

I tried to use discover scsi-target command and it does not give much useful information. and I do not want to add the OS WWNS on my LUN security in addition to HBA WWNS for the host group on the array end.

The problem that I am having is that I can see 7 LUNs out of 9 when I connect to Cisco MDS where as in brocade I can see all the LUNs.

I checked the LUN security and zoning and everything seems to be correct.

If Cisco SAN OS has commands where by I can see what LUNs can be seen on the switch, that would be really helpful. But It looks like LUN/LDEV info cannot be seen through discover command.

Please let me know how to troubleshoot this problem

Thanks

6 REPLIES
Cisco Employee

Re: scsi device discovery in Cisco MDS switches

For the MDS switch to discover LUNS, the SWWN of the vsan needs to be zoned with the PWWN of the target device. That target device needs to have the LUNS exposed to the vsan SWWN in order to answer the report_luns. In an array situation, that would be LUN security needs to configured to answer to the switch's WWN.

New Member

Re: scsi device discovery in Cisco MDS switches

In the array, I tried to add switch wwn to the LUN Security and zoned the same switch wwn on the MDS. Is there anything I am missing. Thanks in advance

But still I could not see any LUNs. When I do discover command, NLUNS shows 0.

and the command sh scsi-target lun os win shows nothing.

discover scsi-target vsan 21 fcid 0xea000b os win

VSAN: 21 FCID: 0xea000b

PRLI RSP: 0x01 SPARM: 0x0012

SCSI TYPE: 31 NLUNS: 0

Vendor: HITACHI Model: DISK-SUBSYSTEM Rev: 5007

Other: 7f:00:03:12:cf:00:00:02

Cisco Employee

Re: scsi device discovery in Cisco MDS switches

It's actually a derivative of the swwn that is used.Issue a "show scsi-target pwwn" and that will show you the pwwn that is used for each OS in the LUN discovery. That is the pwwn that you will want to zone and put in the LUN security.

New Member

Re: scsi device discovery in Cisco MDS switches

Thanks for your help. It worked fine.

It was useful to certain point. Not in greater detail.

It does not show LDEV # information.

Thanks again

--Vijay

New Member

Re: scsi device discovery in Cisco MDS switches

Hi,

Can you pls explain how do we zone Switch's SWWN with Disk Array on MDS Switch ? I know the zoning of Initiators (hosts) n targets but not this ?

Also, does Cisco has it's best practice SAN Environment document somewhere which explains parameters/considerations to be configured/followed in Best possible way unlike some tricky way !!!

Sorry but I'm not trained on Cisco so can you pls help..Thanks...

Cisco Employee

Re: scsi device discovery in Cisco MDS switches

Not sure what you are asking. The SWWN will never talk to the clients. There is a discovery concept where we will query the storage for a REPORT_LUNS and the PWWN that is used for this is show scsi-target pwwn. This PWWN would need to be zoned like any other initiator and also have LUN security configured in an array the same as any other initiator to see the LUNS. Tricky way to do what and document to do what? All of the commands are in the config guide. There is cookbooks and sample configurations on the main website.

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