Dell Command Line Reference Guide for the S4048–ON System 9.14.2.4

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dcb pfc-total-buffer-size

Configure the total buffer size for PFC in kilobytes.

Syntax
dcb pfc-total—buffer—size buffer-size
Parameters
buffer-size
Enter a number in the range of 0 to 7787.
Default
The default is 6592KB.
Command Modes
CONFIGURATION mode
Command History

This guide is platform-specific. For command information about other platforms, see the relevant Dell EMC Networking OS Command Line Reference Guide.

Version
Description
9.11(2.0P0)
Default value is changed from 3088 KB to 2656 KB in the Z9100-ON and S6100-ON.
9.10(0.1)
Introduced on the S6010-ON and S4048T-ON.
9.10(0.0)
Introduced on the S6100.
9.8(1.0)
Introduced on the Z9100–ON.
9.8(0.0P5)
Introduced on the S4048–ON.
9.7(0.0)
Introduced on the S6000-ON.
9.6(0.0)
Introduced on the S5000.
9.3(0.0)
Introduced on the S6000, S4810, and S4820T.
Usage Information

Configure the maximum buffer available for PFC traffic. You can choose to increase or decrease the buffer size that is allocated in the system by default. However, if you modify the PFC buffer size lower than the previously configured size, the system determines whether this reduction in size is valid without disrupting the existing configuration. In such a scenario, disable and re-enable DCB.

The lossless queue limit per port is validated based on the dcb pfc-queues command. PFC queue configuration identifies the maximum number of queues a port can support. Although the queue limit per port is a baseline when dynamic buffering is enabled, the limit per port for queues depends on the availability of the buffer.

Example
DellEMC(conf)#dcb pfc-total-buffer-size 2800
DellEMC(conf)#

DellEMC#show dcb

DCB Status: Enabled, PFC Queue Count: 2

Total Buffer:         Total available buffer excluding the buffer pre-allocated
                      for guaranteed services like global headroom, queue's min
                      guaranteed buffer and CPU queues.

PFC Total Buffer:     Maximum buffer available for lossless queues.

PFC Shared Buffer:    Buffer used by ingress priority groups for shared usage.

PFC Headroom Buffer:  Buffer used by ingress priority group for shared headroom usage.
PFC Available Buffer: Current buffer available for new lossless queues to be
                      Provisioned.

stack-unit Total Buffer PFC Total Buffer PFC Shared Buffer PFC Headroom Buffer PFC Available Buffer
      PP            (KB)             (KB)              (KB)                (KB)                 (KB)
-----------------------------------------------------------------------------------------------------
1     0.0    3399         2800             1040              1040                711
1     0.1    3399         2800             1040              1040                720
1     0.2    3399         2800             1040              1040                711
1     0.3    3399         2800             1040              1040                720
DellEMC#  
DellEMC(conf)#dcb pfc-total-buffer-size 2000
% Error: Total buffer size should not be less than the buffer consumed already in the system
DellEMC(conf)# 

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