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October 4th, 2023 13:10

External Identity issue on VMAX

Hello All, 

We have a situation, i am hoping someone can help us with this.

We have 1 VMAX and 1 Powermax System. Our previous storage team did NDM between these 2 systems. Now for a lot of LUNS on Powermax, i see external identity (WWPN) of the LUN resembles the vmax. We came to know that this is common for the systems which are involved in NDM.

Now, we are going to decommission the VMAX system. I would like to know if we power off the VMAX whatever LUNS on PMAX which have identity as VMAX gets impacted or not.

I could unmap the LUNS on PMAX and reset the identity, but that will need downtime. I see this issue on thousands on LUNs and frankly we won't be able to get approval for downtime on all the servers. So, if someone came across this or have any kind of information, please let me know.

Please let me know if you have any questions. 

 

P.S we do not have support for this VMAX system, so couldnt get help from EMC support.

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October 4th, 2023 19:17

Hi,

Thank you for your question.

Was the move identity feature used when you did the NDM? https://dell.to/3Q4MI5M

Let us know if you have any additional questions.

Thanks,

Josh #Iwork4Dell

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October 4th, 2023 20:12

@DELL-Josh Cr​ Thanks for responding. Actually, I am not sure. We have taken up this project few months back. NDM is done couple of years back, so we are not sure how it was done. Is there a way we can check that ?

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04-10-2023 08:46 PM

It may be in the logs, but if it has been a few years entries that old may have fallen off. https://dell.to/3Q4eMGn
-move_identity: This option assigns the target devices the identity of the source devices. If -move_identity is not selected, host applications need to be directed to the new target volumes prior to rebooting the application. This is not the case if move_identity is selected, much like NDM whereby the host sees what it perceives as the original volumes but with a spoofed WWN. (See the relevant NDM section for more information about WWN manipulation.)

https://dell.to/3F5Boje

Thanks,

Josh

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October 25th, 2023 21:33

@DELL-Josh Cr​ Thanks for your response. We do not want to change the LUN ID or the WWPN identity. 

As you mentioned that the volume will have a spoofed WWN, if we decommission\Shut down the source storage box, will it impact the LUNs coming from new storage box which have a spoofed WWN.

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26-10-2023 01:08 PM

Are you able to not decommission the old storage? I don't see a way to do this without making the LUNs not work. 

Thanks,

Josh

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November 2nd, 2023 19:00

We did not attempt to decommission the old storage. We are worried if we remove the plugs on the old storage box, the LUNS from the new storage box will become inaccessible. 

These external WWPNS are just the identities right. All the LUNS are actually from new system and the data is also storage in the LUNS from new system. So, do you really think the LUNS will be impacted if we remove the old system. We have removed all the masking views from old system. It is just having older LUNS in it. 

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