show buffers

To display statistics for the buffer pools on the network server, use the show buffers EXEC command.

Syntax Description

address	(Optional) Displays buffers at a specified address.
hex-addr	Address, in hexadecimal notation, of the buffer to display.
all	(Optional) Displays all buffers.
assigned	(Optional) Displays the buffers in use.
failures	(Optional) Displays buffer allocation failures.
free	(Optional) Displays the buffers available for use.
old	(Optional) Displays buffers older than one minute.
dump	(Optional) Shows the buffer header and all data in the display.
header	(Optional) Shows only the buffer header in the display.
packet	(Optional) Shows the buffer header and packet data in the display.
input-interface	(Optional) Displays interface pool information. If the specified interface-type has its own buffer pool, displays information for that pool.
interface-type	Value of interface-type can be ethernet, fastethernet, loopback, serial, or null.
identifier	Identifier of the interface specified in interface-type.
pool	(Optional) Displays buffers in a specified buffer pool.
pool-name	Specifies the name of a buffer pool to use.

Command Modes

EXEC

Command History

Release	Modification
10.0	This command was introduced.

Examples

The following is sample output from the show buffers command with no arguments, showing all buffer pool information:

Router# show buffers

 
Buffer elements:
     398 in free list (500 max allowed)
     1266 hits, 0 misses, 0 created
 
Public buffer pools:
Small buffers, 104 bytes (total 50, permanent 50):
     50 in free list (20 min, 150 max allowed)
     551 hits, 0 misses, 0 trims, 0 created
Middle buffers, 600 bytes (total 25, permanent 25):
     25 in free list (10 min, 150 max allowed)
     39 hits, 0 misses, 0 trims, 0 created
Big buffers, 1524 bytes (total 50, permanent 50):
     49 in free list (5 min, 150 max allowed)
     27 hits, 0 misses, 0 trims, 0 created
VeryBig buffers, 4520 bytes (total 10, permanent 10):
     10 in free list (0 min, 100 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
Large buffers, 5024 bytes (total 0, permanent 0):
     0 in free list (0 min, 10 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
Huge buffers, 18024 bytes (total 0, permanent 0):
     0 in free list (0 min, 4 max allowed)
     0 hits, 0 misses, 0 trims, 0 created
          
Interface buffer pools:
Ethernet0 buffers, 1524 bytes (total 64, permanent 64):
     16 in free list (0 min, 64 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache
Ethernet1 buffers, 1524 bytes (total 64, permanent 64):
     16 in free list (0 min, 64 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache
Serial0 buffers, 1524 bytes (total 64, permanent 64):
     16 in free list (0 min, 64 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache
Serial1 buffers, 1524 bytes (total 64, permanent 64):
     16 in free list (0 min, 64 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache
TokenRing0 buffers, 4516 bytes (total 48, permanent 48):
     0 in free list (0 min, 48 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache
TokenRing1 buffers, 4516 bytes (total 32, permanent 32):
     32 in free list (0 min, 48 max allowed)
     16 hits, 0 fallbacks
 
0 failures (0 no memory)
 

Table 96 describes significant fields shown in the display.

Table 96: show buffers Field Descriptions

Field	Description
Buffer elements	Buffer elements are small structures used as placeholders for buffers in internal operating system queues. Buffer elements are used when a buffer may need to be on more than one queue.
free list	Total number of the currently unallocated buffer elements.
max allowed	Maximum number of buffers that are available for allocation.
hits	Count of successful attempts to allocate a buffer when needed.
misses	Count of buffer allocation attempts that resulted in growing the buffer pool to allocate a buffer.
created	Count of new buffers created to satisfy buffer allocation attempts when the available buffers in the pool have already been allocated.
Public buffer pools:
Small buffers	Buffers that are 104 bytes long.
Middle buffers	Buffers that are 600 bytes long.
Big buffers	Buffers that are 1524 bytes long.
VeryBig buffers	Buffers that are 4520 bytes long.
Large buffers	Buffers that are 5024 bytes long.
Huge buffers	Buffers that are 18024 bytes long.
total	Total number of this type of buffer.
permanent	Number of these buffers that are permanent.
free list	Number of available or unallocated buffers in that pool.
min	Minimum number of free or unallocated buffers in the buffer pool
max allowed	Maximum number of free or unallocated buffers in the buffer pool
hits	Count of successful attempts to allocate a buffer when needed.
misses	Count of buffer allocation attempts that resulted in growing the buffer pool in order to allocate a buffer.
trims	Count of buffers released to the system because they were not being used. This field is displayed only for dynamic buffer pools, not interface buffer pools, which are static.
created	Count of new buffers created in response to misses. This field is displayed only for dynamic buffer pools, not interface buffer pools, which are static.
Interface buffer pools:
total	Total number of this type of buffer.
permanent	Number of these buffers that are permanent.
free list	Number of available or unallocated buffers in that pool.
min	Minimum number of free or unallocated buffers in the buffer pool.
max allowed	Maximum number of free or unallocated buffers in the buffer pool.
hits	Count of successful attempts to allocate a buffer when needed.
fallbacks	Count of buffer allocation attempts that resulted in falling back to the public buffer pool that is the smallest pool at least as big as the interface buffer pool.
max cache size	Maximum number of buffers from that interface's pool that can be in that interface buffer pool's cache. Each interface buffer pool has its own cache. These are not additional to the permanent buffers; they come from the interface's buffer pools. Some interfaces place all of their buffers from the interface pool into the cache. In this case, it is normal for the free list to display 0.
failures	Total number of allocation requests that have failed because no buffer was available for allocation; the datagram was lost. Such failures normally occur at interrupt level.
no memory	Number of failures that occurred because no memory was available to create a new buffer.

The following is sample output from the show buffers command with an interface type and number:

Router# show buffers Ethernet 0

 
Ethernet0 buffers, 1524 bytes (total 64, permanent 64):
     16 in free list (0 min, 64 max allowed)
     48 hits, 0 fallbacks
     16 max cache size, 16 in cache