[f-nsp] Flow Control specifics for different speed interfaces

[Nick Cutting]

I have this on some of my FCX's

They have 10g uplinks (set 2) and 1 g links to servers / Sans (set 1)

symmetric-flow-control enable
symmetric-flow-control set 1 xoff 60 xon 50
symmetric-flow-control set 2 xoff 60 xon 50
symmetric-flow-control set 1 buffers 64
symmetric-flow-control set 2 buffers 1632

The iSCSI best practice document says to turn on flow control - but not to set individual values.

Do you brocade experts see any harm in removing these - I'm not sure how my predecessor came to add these and why these values were chosen - perhaps going from 10g interfaces to 1 g interfaces and or for buffers etc.

Thanks,

The relevant part of the guide does not mention WHY you would change these values:

symmetric-flow-control set
Sets symmetric flow control parameters.
Syntax
symmetric-flow-control set port-type { buffers value [ unit unit-value ] | xoff num xon num }
no symmetric-flow-control set port-type { buffers value [ unit unit-value ] | xoff num xon num }
Command Default
1G: Buffers: 272; XOFF Limit: 91; XON Limit: 75
10G: Buffers: 416; XOFF Limit: 91; XON Limit: 75
Parameters
port-type
Specifies the port type. The port type can be one of the following:
1
Sets the buffer limits or XOFF and XON limits for 1G ports.
2
Sets the buffer limits or XOFF and XON limits for 10G ports.
3
Sets the buffer limits or XOFF and XON limits for 100G ports.
buffers value
Sets the total buffer limits. The value can range from 64 through 320 for 1G ports and from 64 through 1632 for 10G ports. The default value for 1G ports is 272 and for 10G ports is 416 .
unit unit-value
Specifies the buffer limit for a stack unit.
xoff num
Sets the XOFF limit. The minimum value is 60 percent, and the maximum value is 95 percent.
xon num
Sets the XON limit. The minimum value is 50 percent and the maximum value is 90 percent.
Modes
Global configuration mode
Usage Guidelines
Use the show symmetric command to view the default or configured buffer limit or XON and XOFF thresholds.
The no form of the command deletes the configured symmetric flow control values.
Examples
The following example changes the thresholds for all 1G ports.
device(config)# symmetric-flow-control set 1 xoff 91 xon 75
The following example changes the total buffer limit for all 10G ports.
device(config)# symmetric-flow-control set 2 buffers 128

Total buffers modified, 1G: 320, 10G: 128


Thanks Nick
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