wwn number changing after sp replacement

The wwn number should not change as they are constant world wide. If they are changing probably there is a issue with part. I would suggest you to contact the EMC support team.

for every cpu module the wwn number is unique right.... then  how the new module will retain the old wwn ??? how it will change its new wwn to old ??

Replacing a SP will not change the WWN. The world wide number is associated with the Storage Processor Enclosure - new SP will get the same WWN.

If you look up the Clariion's wwn, you can derive the SP port's wwn's from :

SPA1 = 61
SPA2 = 62
SPA3 = 63

SPB0 = 68
SPB1 = 69
SPB2 = 6A
SPB3 = 6B

The wwn is kind of software generated by the "backplane" of the Clariion and has nothing to do with the Storage Processors themselves. One CLARiiON - all SP Ports are having same WWNN - only the port names (WWPN) differs for individual SP ports. For a given CLARiiON system - the idea is to retain the WWNN even after any hardware or component replacement or platform upgrade.

The activity is Online - however, SPB will be removed from the System - means, all LUNs owned by SPB will be trespassed to SPA - ensure all the hosts connected are running proper failover software. It may be a good idea to do this activity during downtime or low activity period time.

Just trying to convey the same as what Vishal said but in few words

MIght help

Let me explain you how the wwns are given on the clariion

Each Storage Processor Port will have a unique World Wide Name associated with it. What we are doing on this page is to “break down” what makes up the SP Port WWN. What I am showing here are the three(3) pieces that make up the WWN. The three(3) pieces are what I am calling the ‘EMC Flag’, the SP Port Identifier, and the Array ID. All SP Port WWNs on Clariions start with the same ‘EMC Flag’ of 50:06:01. When you are looking at the Switch Software that shows the ports on the switch and what is plugged into those ports, anytime you see a World Wide Name that starts with the 50:06:01, you will know that a Clariion SP Port is connected there.

The next “piece” to the World Wide Name, is the SP Port Identifier. On all Clariions, these numbers are the same as well. For instance, if you have 3 Clariions in your environment, every one of those Clariion’s SPA Port 0 World Wide Name would start off 50:06:01:60. And every Clariion’s SP B Port 1 would start off 50:06:01:69. These SP Port Identifiers will not change from Clariion to Clariion.

The last “piece” to the puzzle is the Array ID. This is related to the Unique ID of the Clariion itself. Every Clariion has a unique World Wide Name associated with it. But, that Array ID belongs to every port on that Clariion as it shows above. Now, if you have two(2) Clariions in your environment, you will see two(2) sets of Array IDs. Let’s say you have a Production Clariion and a Development Clariion (I know, no one has that), the Production Clariion could have an Array ID of 10:60:08:74, and the Development Clariion could have an Array ID of 10:60:06:23. So, the Production Clariion’s SP A Port 0 would be 50:06:01:60:10:60:08:74, and the Development Clariion’s SP A Port 0 would be 50:06:01:60:10:60:06:23.

The fourth octet (e.g., 60 in this example) contains the port and service processor, which can be identified by comparing the value to the following chart:

60 – SPA port 0
61 – SPA port 1
62 – SPA port 2
63 – SPA port 3
68 – SPB port 0
69 – SPB port 1
6A – SPB port 2
6B – SPB port 3

So in the case of WWPN 50:06:10:60:10:F3:84, the value 60 would map to service process A, port 0

so when you replace the SP the same above step is followed. Hence there is not change in the wwns.

Hope this answers your question.