Fibre Channel (SAN)

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Occasional Contributor
Posts: 6
Registered: ‎05-06-2009

Buffer credits

We have several storage systems (EMC and HP) with 16Gbps FA-ports.

 

Recently I went into a dialogue with a guy from another service provider aiming, that if using SAN switches with 16Gbps ports and hosts with 16Gbps HBA´s, Buffer Credit on the SAN switch ports must be set to 16 and not only 8.

 

My second questions is:

What is the recommended Buffer Credit size for 16Gbps SW ISL´s/IFL´s?

 

Brocade Moderator
Posts: 284
Registered: ‎08-31-2009

Re: Buffer credits

Hello,

 

Buffers are nogociated based on the port speed, so no matter with this.

Concerning your other question, I suppose you mean the number of BB credits? Because BB credit size may vary depending the amount of data sent (payload) and it is automatic based on Fiber Channel protocol.

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution"
Brocade Moderator
Posts: 241
Registered: ‎03-29-2011

Re: Buffer credits

For standard F-ports (none F-port trunking or non QoS), the switch will allocate 8 buffers which can be increased with portcfgfportbuffers. In normal circumstances this would not be necesary (cut through routing is used). On the attached device, it is of course dependen on speed, hardware, software etc. With Gen6, 32G F-port, we go 20 buffer on the switch - see attached extract from the FOS 8.0.1 AG:

 

fos-801-admin-guide-buffer-credit-per-port.PNG




If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution".

Any and all information provided by me is not reviewed, approved or endorsed by Brocade and is provided solely as a convenience for Brocade customers. All systems and all networks are different and unique. If you have a service affecting network problem, please open a TAC service request for service through Brocade, or through your OEM equipment provider. If this provided you with a solution to this issue, please mark it with the button at the bottom "Accept as solution"

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