System information

Adjusting Buffers
Book Title
15-334
• misses identifies the number of times a buffer has been requested and the RP detected that
additional buffers were required. (In other words, the number of buffers in the free list has
dropped below min.) The misses counter represents the number of times the RP has been forced
to create additional buffers.
• trims identifies the number of buffers that the RP has trimmed from the pool when the number
of buffers in the free list exceeded the number of max allowed buffers.
• createdidentifies the number of buffers that have been created in the pool. The RP creates buffers
when demand for buffers has increased until the number of buffers in the free list is less than min
buffers and/or a miss occurs because of zero buffers in the free list.
• failures identifies the number of failures to grant a buffer to a requester even after attempting to
create an additional buffer. The number of failures represents the number of packets that have
been dropped due to buffer shortage.
• no memory identifies the number of failures caused by insufficient memory to create additional
buffers.
The show buffers command output in Figure 15-8 indicates high numbers in the trims and created
fields for large buffers. If you are receiving high numbers in these fields, you can increase your serial
link performance by increasing the max free value configured for your system buffers. trims
identifies the number of buffers that the RP has trimmed from the pool when the number of buffers
in free list exceeded the number of max allowed buffers.
Use the buffers max free number global configuration command to increase the number of free
system buffers. The value you configure should be approximately 150% of the figure indicated in the
total field of the show buffers command output. Repeat this process until the show buffers output
no longer indicates trims and created buffers.
If the show buffers command output shows a large number of failures in the (no memory) field (see
the last line of output in Figure 15-8), you must reduce the usage of the system buffers or increase
the amount of shared or main memory (physical RAM) on the router. Call your technical support
representative for assistance.