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MDS9509 logging into EMC CX4-960 as an initiator

Looking in the NAvisphere Manager I see the mds logging into the array on every port in the array.  But, the connection is not registered with the array.  This just started about two months ago after an upgrade to 4.13a.

EMC has no answers as to why this is happening or how to handle it.

Any suggestions would be of great help.

  • Storage Networking
2 ACCEPTED SOLUTIONS

Accepted Solutions

Re: MDS9509 logging into EMC CX4-960 as an initiator

The MDS tries to identify devices that FLOGI into it by doing a PLOGI back to the device. If the PLOGI is successful, it will then PRLI and issue a

SCSI inquiry command to see what the device is and what capabilities it has.  If the PLOGI is rejected, then the MDS stops the discovery process.  Some arrays reject the PLOGI due to lun masking, and it's up to the hosts to discovery what the array capabilities are.  Did you by chance install one of the SSM or MSM line cards at the same time?  I know that if one of these 'intelligent' line cards is installed, the MDS might be more agressive in trying to discover what devices are installed to permit provisioning of the advances features like SAN tap and other intelligent applications.


Hopefully this should not be causing any functional impact, if it is let us know and we can investigate further.

  Mike

Re: MDS9509 logging into EMC CX4-960 as an initiator

I'm not sure why it would show up with the 4.1.3a, and not before if the MSM cards were there all along.  I see no reason that the MDS intiators can not be removed from the Clarion.  If the Clarion logs out and back into the facric, they may re-appear as the MDS will try again to discover what they are.

I believe you can disable this discovery process on the MDS with the following configuration command.

no scsi-target discovery

Hope this helps,
Mike

5 REPLIES

Re: MDS9509 logging into EMC CX4-960 as an initiator

The MDS tries to identify devices that FLOGI into it by doing a PLOGI back to the device. If the PLOGI is successful, it will then PRLI and issue a

SCSI inquiry command to see what the device is and what capabilities it has.  If the PLOGI is rejected, then the MDS stops the discovery process.  Some arrays reject the PLOGI due to lun masking, and it's up to the hosts to discovery what the array capabilities are.  Did you by chance install one of the SSM or MSM line cards at the same time?  I know that if one of these 'intelligent' line cards is installed, the MDS might be more agressive in trying to discover what devices are installed to permit provisioning of the advances features like SAN tap and other intelligent applications.


Hopefully this should not be causing any functional impact, if it is let us know and we can investigate further.

  Mike

New Member

Re: MDS9509 logging into EMC CX4-960 as an initiator

Yes, We do have MSM cards installed, But they have been there since they were first brought online.  It's not a big problem just one we would like an answer to as why did it happen and can they be safely removed from the Clariion array and not return.

Seems this issue came up after an upgrade to Cisco 4.13a.

Fred

Re: MDS9509 logging into EMC CX4-960 as an initiator

I'm not sure why it would show up with the 4.1.3a, and not before if the MSM cards were there all along.  I see no reason that the MDS intiators can not be removed from the Clarion.  If the Clarion logs out and back into the facric, they may re-appear as the MDS will try again to discover what they are.

I believe you can disable this discovery process on the MDS with the following configuration command.

no scsi-target discovery

Hope this helps,
Mike

New Member

Re: MDS9509 logging into EMC CX4-960 as an initiator

Mike,

Thank You.  Worked perfectly.

New Member

Re: MDS9509 logging into EMC CX4-960 as an initiator

Mike,

I may have spoken too soon.  The unregistered logins are back.  No reboot/reset of the array or switch took place.  They disappeared after running the NO SCSI-TARGET DISCOVERY, and didn't appear few a few days ( or until we chaecked it ).

We have no iscsi running , no NPV or ISL's.

Any more thoughts?

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