Deciding To Tune Buffers; Buffer Tuning Commands - Dell PowerEdge M IO Aggregator Command Reference Manual

Deciding to Tune Buffers

Dell Force10 recommends exercising caution when configuring any non-default buffer settings, as tuning
can significantly affect system performance. The default values work for most cases.
As a guideline, consider tuning buffers if traffic is very bursty (and coming from several interfaces). In this
case:
• Reduce the dedicated buffer on all queues/interfaces.
• Increase the dynamic buffer on all interfaces.
• Increase the cell pointers on a queue that you are expecting will receive the largest number of packets.

Buffer Tuning Commands

To tune the buffers, use the following commands:
Task
Define a buffer profile for the FP queues.
Define a buffer profile for the CSF queues.
Change the dedicated buffers on a physical 1G
interface.
Change the maximum amount of dynamic buffers
an interface can request.
Change the number of packet-pointers per queue.
Apply the buffer profile to a CSF to FP link.
FTOS Behavior: If you attempt to apply a buffer profile to a non-existent port-pipe, FTOS displays the
following message. However, the configuration still appears in the running-config.
%DIFFSERV-2-DSA_BUFF_CARVING_INVALID_PORT_SET: Invalid FP port-set 2 for linecard 2. Valid
range of port-set is <0-1>
Configuration changes take effect immediately and appear in the running configuration. Because under
normal conditions all ports do not require the maximum possible allocation, the configured dynamic
allocations can exceed the actual amount of available memory; this is called oversubscription. If you
choose to oversubscribe the dynamic allocation, a burst of traffic on one interface might prevent other
interfaces from receiving the configured dynamic allocation, which causes packet loss.
Command
buffer-profile fp fsqueue
buffer-profile csf csqueue
buffer dedicated
buffer dynamic
buffer packet-pointers
buffer csf linecard
Command Mode
CONFIGURATION
CONFIGURATION
BUFFER PROFILE
BUFFER PROFILE
BUFFER PROFILE
CONFIGURATION
Debugging and Diagnostics | 259