Big buffer misses in 4510 switch, should I tune?

[ubuntu_guy]

Big buffers, 1536 bytes (total 86, permanent 50, peak 114 @ 4d13h):

     86 in free list (5 min, 150 max allowed)

     12795878 hits, 285 misses, 819 trims, 855 created

     0 failures (0 no memory)

I'm just looking for some general input on tuning the buffer pools manually. Any best practices, or gotcha's I need to be aware of? The switch is a catalyst 4510R+E.

[Yogesh Ramdoss]

Richard,

As you might be aware, "show buffers" command show the CPU buffers used for process-switched or cpu-destined traffic.

The output tells me that Cat4510 requred almost 114 Big Buffers at one point of time, when max allowed is 86.

if I were you, I will try to find the reason why so many packets (that require 1536 byte buffers) sent to the CPU ?

Either we had high number of process-switched traffic, or traffic sent to CPU itself.

Good documents on buffer failures and tuning:

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a7b80.shtml

http://www.cisco.com/en/US/products/hw/modules/ps2643/products_tech_note09186a0080093fc5.shtml

Hope this helps.

- Yogesh