Fibre Channel (SAN)

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New Contributor
Posts: 4
Registered: ‎05-24-2012

ASIC boundaries

Hi,

I have a 24 port 8Gb SAN switch.

To get the best performance out of the switch I would like to connect the storage array to port 0,4,8 and 12.

Does anybody know how the ASIC's are allocated (wired)?

Or is it better to make an offset of 8 ?

Thx

Steve

External Moderator
Posts: 4,813
Registered: ‎02-23-2004

Re: ASIC boundaries

--->>> I have a 24 port 8Gb SAN switch.

I assume you have Brocade 300 ?

All 24 Port in Brocade 300, are Associated / Addressed to single ASIC


TechHelp24
New Contributor
Posts: 4
Registered: ‎05-24-2012

Re: ASIC boundaries

Thanks for the quick answer,

yeah I am using a Brocade 300.

How can I understand that?

Each port has its own ASIC?

Or are all 24 ports sharing a single ASIC.

So in general, it wouldn't make sense to share the load over different ASIC boundaries?

What I try to explain is: It's not important if I connect the storage array into port 0,1,2,3?

External Moderator
Posts: 4,813
Registered: ‎02-23-2004

Re: ASIC boundaries

Brocade 300 have only One GoldenEye2 ASIC

This "ONE" ASIC provide all 24 Ports.

TechHelp24
New Contributor
Posts: 4
Registered: ‎05-24-2012

Re: ASIC boundaries

So it's not important if, I connect the storage array into port 0,1,2,3?

The reason why I ask this is, an Engineer from HP told me to connect the storage array into port 0,8,15,22.

He told me this is better for performance and high availability.

External Moderator
Posts: 4,813
Registered: ‎02-23-2004

Re: ASIC boundaries

Port Groups, 0-7; 8-15; and 16-23; called Octet are relevant by Trunking, because the Trunking feature can be bounded only betwen the same Octet.

--->>>an Engineer from HP told me to connect the storage array into port 0,8,15,22.

Port 0, is in Octet Group 1;

Port 8 and 15 are in Octet Group 2;

Port 22 is in Octet Group 3;

ask this HP Engineer, what is the difference instead to connect Array to Port "22" maybe to another Port 16-23 ?

and why get a better Performance when Array is connected to Port 8 and 15 ?

TechHelp24
New Contributor
Posts: 4
Registered: ‎05-24-2012

Re: ASIC boundaries

Port 23 is used for ISL.

Maybe this is the reason.

Your explanations make sense to me.

Of course I'll ask the guy.

Anyways, thanks for the quick response!

Steve

External Moderator
Posts: 4,813
Registered: ‎02-23-2004

Re: ASIC boundaries

Steve,

--->>> Of course I'll ask the guy.

I would be curious about the argumentation from HP.

--->>> Port 23 is used for ISL. Maybe this is the reason.

change nothing in such case if Port 23 or xy is used for ISL

Another example:

such an Argumentation like this from HP Engineer make sense by Multi ASIC, e.g. Blade based switches, see attached ASIC layout.

as you can see, in such case 8G 32 Port Blade is based on TWO ASIC,

Port 0-7; 16-23; are Assigned to ASIC 0

Port 8-15; 24-31 are assigned to ASIC 1

FC8-32 ASIC.jpg

TechHelp24
Frequent Contributor
Posts: 141
Registered: ‎05-26-2009

Re: ASIC boundaries

If you reach the storage array from hosts connected to other switches over an ISL, maybe he wanted to avoid a situation like this:

How to NOT connect an SVC in a core-edge Brocade fabric (seb's sanblog)

Beside of that I'm not aware of any other effects that would influence the decision.

I would just connect it at random ports. 0, 8, 15, 22 sounds good

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