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Not using BUS 0 on a VNX5600

Hi All,

Will it cause any performance impact or any other issues if there are no DAEs on BUS 0 on a VNX5600? All the DAEs - 17 total - are balanced across BUSES 1,2,3,4,5. I know it would be best to load balance them across all the available buses, but it is already cabled and initialized omitting bus 0. So bus 0 can be used for the future expansion. Maybe it is worth re-cabling the array and utilizing all the buses?

Appreciate your input.

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16 Replies
cypherstrength
1 Nickel

Re: Not using BUS 0 on a VNX5600

My opinion is that you should recable it with alternating buses.  For example, the first few DAE's would be 0_0, 1_0, 2_0, 3_0, etc....

This allows for all buses to be used early on in the expansion. 

Mike

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Re: Not using BUS 0 on a VNX5600

I agree that all the available buses should be utilized. However, if they are not, it will not cause a performance issue, will it?

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Sheron1
2 Iron

Re: Not using BUS 0 on a VNX5600

Does it have any lag?

As per EMC that config would not be correct confid Ad-astra.

Will it work? Yes practicality it should

Will that create a problem? High chances of yes

And if there is a performance issue then the first recommendation would be to re-configure.

Maybe it is worth re-cabling the array and utilizing all the buses?>> Oh yes

Regards,

Sheron.

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cypherstrength
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Re: Not using BUS 0 on a VNX5600

It will cause in imbalance.  Depends on how hard you push the array and the other available buses.  Also, if you dont have 0_0 cables, im not sure if it will work.  I believe vault has to be in and cables to 0_0

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Re: Not using BUS 0 on a VNX5600

0_0 is the DPE - it is VNX5600. It is already up and running.

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Re: Not using BUS 0 on a VNX5600

Thanks Sheron, please see my comments on bold.

Does it have any lag? - Unknown, there is no production data on it yet.

As per EMC that config would not be correct confid Ad-astra. - This is funny, because EMC field services engineers cabled it this way, omitting bus 0. I guess, if it goes against EMC best practices, they should have brought this up, not me, after it is cabled and initialized.

Will it work? Yes practicality it should - It does work, at least it is up and running, no prod data on it yet.

Will that create a problem? High chances of yes - Why will it create a problem? Could you elaborate on this.

And if there is a performance issue then the first recommendation would be to re-configure. - I agree, but it will depend on the nature of the problem.

Maybe it is worth re-cabling the array and utilizing all the buses?>> Oh yes - I agree, just wanted to find out what complications may come out of it.

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cypherstrength
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Re: Not using BUS 0 on a VNX5600

If this no prod data on it, I would re-cable. Like I said, off the bat, your Buses wont be balanced as Bus 0 wont be in use.

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Sheron1
2 Iron

Re: Not using BUS 0 on a VNX5600

Here is what could help us

https://support.emc.com/docu47537_VNX5600-Hardware-Information-Guide.pdf?language=en_US

From page 128 to be precise.

Honestly I can think of many issues but cant find any docs to prove my point. Gimme a lil more time to think to figure what could be the issue.

Regards,

Sheron

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Sheron1
2 Iron

Re: Not using BUS 0 on a VNX5600

As per what I understand I would think think that the BUS 0 is kept only for the DPE.

So BUS 0 is free at the moment if we need to add any enclosure to it.I should be able to use the BUS 0 for future use.

Error: ?? , i was thinking about any parity mismatches due to the way the array is connected.

However how practical is the error to show up is something I honestly dont know.

Can you check with the support team and see what they think of it.

If you get a green flag from them then , yaaaaay, we are good.

If they say no can you let us know why, as it would help me clear my doubt.

Thank you Ad_astra, you made me think a bit today

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