Managing Dynamic Buffer Sharing; Monitoring The Qos Packet Buffer - Cisco Nexus 9000 Series Configuration Manual

Managing Dynamic Buffer Sharing

The hardware qos min-buffer command is used to control the QoS shared buffer.
hardware qos min-buffer [all|default|none]
The show hardware qos min-buffer command is used to display the current buffer configuration.
Managing Dynamic Buffer Sharing
Beginning with NX-OS 7.0(3)I7(4), dynamic buffer sharing (egress buffering) across slices is configured
with the hardware qos dynamic-buffer-sharing command. Following the command, you must reload the
switch to enable the dynamic buffering.
Buffer sharing is enabled by dynamic bank allocation (1 bank = 4k cells, 1 cell = 416 bytes) and controlled
by a global controller (eCPU) that manages the banks being distributed among slices. Dynamic buffer sharing
provides six reserved banks (10MB) for each slice and twelve banks for sharing across slices (20MB).
Note Dynamic Buffer Sharing is supported only on Nexus 9300-FX2 platform switches, see
Support Matrix

Monitoring the QoS Packet Buffer

The Cisco Nexus 9000 Series device has a 12-MB buffer memory that divides into a dedicated per port and
dynamic shared memory. Each front-panel port has four unicast queues and four multicast queues in egress.
In the scenario of burst or congestion, each egress port consumes buffers from the dynamic shared memory.
You can display the real-time and peak status of the shared buffer per port. All counters are displayed in terms
of the number of cells. Each cell is 208 bytes in size. You can also display the global level buffer consumption
in terms of consumption and available number of cells.
Note
Monitoring the shared buffer on ALE enabled devices is not supported for the port level.
Note In the examples shown in this section, the port numbers are Broadcom ASIC ports.
This example shows how to clear the system buffer maximum cell usage counter:
Cisco Nexus 9000 Series NX-OS Quality of Service Configuration Guide, Release 7.x
130
Configuring Queuing and Scheduling
• all
Current behavior where all reservations are
enabled ON).
• default
Enables reservations only for qos-group-0.
• none
Disables reservations for all qos-groups.
Nexus Switch Platform