FAS and V-Series Storage Systems Discussions

Stack Same Path warning... recabling advice.

I am getting "Stack Same path" warning when running Config Advisor. This is because of the connectivity of the primary and redundant path on four stack of FC shelves  look like this:

1d, 1c

3d, 3c

11b, 11a

4d, 4c

I guess what this means, is if the module (example IOM on port 1 where 1d and 1c) breaks, then I lose the entire stack, am I right? potential loss of data? especially since we are using software base ownership (disk assign)

I plan to recable them, but I want to learn more, but I plan to recable them like these:

1d, 3c

3d, 11a

11b, 4c

4d, 1c

What will be the best approach on recabling them? Total shutdown? anything else need to be done on the OS level?

Thanks,

md

19 REPLIES

Re: Stack Same Path warning... recabling advice.

Keep in mind that most cards (including the onboard ports) have one ASIC chip for two ports, you shouldn't use A&B or C&B ports from the same card on one controller.

You might find easier to cable them using same port such on two different cards, for example 1a/3a, 4a/11a partner could be 1b/3b, 4b/11b. You have a lot of choices.

Re: Stack Same Path warning... recabling advice.

hi, could you please elaborate on why it is not advisable to use A&B or C&B?

Re: Stack Same Path warning... recabling advice.

You are looking for the A&B modules of the disk shelf. I don't understand what you mean by C&B.

For example:

PRIMARY  PORT  SECONDARY PORT SHELF BAY

-------- ----  --------- ---- ---------

4a.24.0   B    3a.24.0    A    24    0

4a.24.1   B    3a.24.1    A    24    1

4a.24.2   B    3a.24.2    A    24    2

In this example B module is the primary and A is the secondary.

Re: Stack Same Path warning... recabling advice.

Hi,

I was just responding to your statement

"you shouldn't use A&B or C&B ports from the same card on one controller.You might find easier to cable them using same port such on two different cards, for example 1a/3a, 4a/11a partner could be 1b/3b, 4b/11b".

I understand the part where you say that  I should use port a on different cards. I thought you were saying that I should not use port 'a' on one card, then port 'c' on another card.

Re: Stack Same Path warning... recabling advice.

Typo, I meant ports A&B are on one ASIC and ports C&D another ASIC.

Re: Stack Same Path warning... recabling advice.

thanks for clarifying. I heard that advise somewhere also but not so sure the reason behind it.

If I change the redundanth path, will I need to do anything else or will it be auto-detected without interruption.

Thanks,

md

Re: Stack Same Path warning... recabling advice.

Once you verify MPHA you should be able to move cables without down time. Do it slowly, one cable at a time then make sure everything is working before moving another cable, storage show disk -p before each move.

Re: Stack Same Path warning... recabling advice.

Hi,

in your sample above, B module is the primary. What determines between A and B module as to which becomes the primary and the redundant?

Re: Stack Same Path warning... recabling advice.

I guess I am now confusing the primary and secondary to the cable redundancy. The primary is the module connected to the owner of the disk. is that correct?

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