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Usage
Information
Configure the maximum shared buffer available for PFC traffic. You can choose to increase or decrease
the shared buffer that is allocated in the system by default. Configure the shared buffer size less than
the total PFC buffer size. If the buffer size and DCB buffer threshold settings are applied on one or more
ports, a validation is performed to determine whether following condition is satisfied: If the shared buffer
size is more than the total PFC buffer size value, the configuration is not saved and a system logging
message is generated as follows:
Shared-pfc-buffer-size <= (Total-pfc-buffer-size — Σpfc priority <> buffer-size on each port, priority).
Dell(conf)#dcb pfc-shared-buffer-size 2000
%ERROR: pfc shared buffer size configured cannot accommodate existing
buffer requirement in the system.
Enter a smaller value for the shared buffer size or increase the total buffer size appropriately by using the
dcb pfc-total- buffer-size command.
Example
Dell(conf)#dcb pfc-shared-buffer-size 5000
dcb pfc-total-buffer-size
Configure the total buffer size for PFC in kilobytes.
Syntax
dcb pfc-total—buffer—size KB
Parameters
KB Enter a number in the range of 0 to 7787.
Default The default is 6592KB.
Command Modes CONFIGURATION mode
Supported Modes Full–Switch
Command
History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.9(0.0) Introduced on the MXL 10/40GbE Switch IO Module.
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. For example, if you
modify the total buffer size as 4000 KB from the previous size of 5000 KB, an error message is displayed
that this reduction cannot be performed owing to existing system configuration because of queues that
are being currently in process.
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.
d.
Example
Dell(conf)#dcb pfc-total-buffer-size 5000
Dell(conf)#dcb pfc-total-buffer-size 4000
%ERROR: Total pfc buffer size configured cannot accommodate existing
buffer requirement in the system.
392 Data Center Bridging (DCB)