To display detailed
information about the buffer pools on the network server when Cisco IOS, Cisco
IOS Software Modularity, or Cisco IOS XE images are running, use the
show
buffers command in user EXEC or privileged EXEC
mode.
show buffers [ {address hex-address | failures | pool pool-name | detailed | processes | {all | assigned [process-id] | free | old | input-interface interface-type interface-number} | [pool pool-name]} [dump | header | packet | location pool-location]]
Cisco Catalyst 4500e Series
Switches running IOS XE software
show buffers [detailed process id {address hex-address | all | assigned | failures | free | input-interface interface-type interface-number | old | pool pool-name} [dump | header | packet | location pool-location]]
Syntax Description
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address
|
(Optional) Displays buffers at a specified address.
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|
hex-address
|
(Optional) Address in hexadecimal notation.
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|
failures
|
(Optional) Displays buffer allocation failures.
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|
pool
|
(Optional) Displays buffers in a specified buffer pool.
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pool-name
|
(Optional) Name of buffer pool.
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|
detailed
process
|
(Optional) Displays detailed buffer information.
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processes
|
(Optional) For Cisco IOS Software Modularity images only. Displays buffers
connected to Packet Manager.
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all
|
(Optional) Displays all buffers.
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assigned
|
(Optional) Displays the buffers in use.
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process-id
|
(Optional) For Cisco IOS Software Modularity images only. POSIX process
identifier.
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free
|
(Optional) Displays the buffers available for use.
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old
|
(Optional) Displays buffers older than one minute.
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input-interface
|
(Optional) Displays interface pool information. If an interface type is
specified and this interface has its own buffer pool, information for that pool
is displayed.
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interface-type
|
(Optional) Interface type.
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interface-number
|
(Optional) Interface number.
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dump
|
(Optional) Displays the buffer header and all data.
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header
|
(Optional) Displays the buffer header only.
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packet
|
(Optional) Displays the buffer header and packet data.
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location
pool-location
|
(Optional) Displays all the buffer pools in a given location. The global buffer
pools come first, followed up with process-level buffer pools.
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Usage Guidelines
Note
|
When you use the
show buffers input-interface [packet | dump] command, some of the data
packets are not displayed correctly because of the way packets are assembled
for display on the CLI.
|
Pointers to the memory location of the header and data for the packet
are stored in local memory. By the time the pointers are de-referenced, it is
possible that the memory storing the header or packet data is overwritten. For
example, in the
show buffers input-interface packet command output, the source and
destination addresses might not match the actual source and destination address
if the packet data were decoded by some secondary means such as analyzing
manually or by other means. It is recommended that the users of this command
must validate packets by a secondary means.
Command Default
If no options are
specified, all buffer pool information is displayed.
Command Modes
User EXEC (>)
Privileged EXEC (#)
Command History
|
Release
|
Modification
|
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10.0
|
This
command was introduced.
|
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12.3
|
The
option to filter display output based on specific buffer pools was expanded.
|
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12.2(18)SXF4
|
Two
additional fields were added to the output to support Cisco IOS Software
Modularity.
|
|
12.2(33)SRA
|
This
command was integrated into Cisco IOS Release 12.2(33)SRA.
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|
Cisco
IOS XE Release 3.1.0.SG
|
This
command was introduced on the Cisco Catalyst 4500e Serfies Switches with
support for the
detailed
process command option.
|
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)
The following is
sample output from the
show
buffers command with no arguments, showing only
buffer pool information for Huge buffers. This output shows a highest total of
five Huge buffers created five days and 18 hours before the command was issued.
Router# show buffers
Huge buffers, 18024 bytes (total 5, permanent 0, peak 5 @ 5d18h):
4 in free list (3 min, 104 max allowed)
0 hits, 1 misses, 101 trims, 106 created
0 failures (0 no memory)
The following is
sample output from the
show
buffers command with no arguments, showing only
buffer pool information for Huge buffers. This output shows a highest total of
184 Huge buffers created one hour, one minute, and 15 seconds before the
command was issued.
Router# show buffers
Huge buffers, 65280 bytes (total 4, permanent 2, peak 184 @ 01:01:15):
4 in free list (0 min, 4 max allowed)
32521 hits, 143636 misses, 14668 trims, 14670 created
143554 failures (0 no memory)
The following is
sample output from the
show
buffers command with an interface type and
interface 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
The table below
describes the significant fields shown in the display.
Table 13. show buffers (Cisco IOS Software) Field Descriptions
|
Field
|
Description
|
|
Buffer
elements
|
Small
structures used as placeholders for buffers in internal operating system
queues. Used when a buffer may need to be on more than one queue.
|
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free list
|
Total
number of the currently unallocated buffer elements.
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max
allowed
|
Maximum
number of buffers that are available for allocation.
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hits
|
Count of
successful attempts to allocate a buffer when needed.
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misses
|
Count of
buffer allocation attempts that resulted in growing the buffer pool to allocate
a buffer.
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created
|
Count of
new buffers created to satisfy buffer allocation attempts when the available
buffers in the pool have already been allocated.
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Public
Buffer Pools
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|
Small
buffers
|
Buffers
that are 104 bytes long.
|
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Middle
buffers
|
Buffers
that are 600 bytes long.
|
|
Big
buffers
|
Buffers
that are 1524 bytes long.
|
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VeryBig
buffers
|
Buffers
that are 4520 bytes long.
|
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Large
buffers
|
Buffers
that are 5024 bytes long.
|
|
Huge
buffers
|
Buffers
that are 18,024 bytes long.
|
|
total
|
Total
number of this type of buffer.
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permanent
|
Number of
these buffers that are permanent.
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peak
|
Maximum
number of buffers created (highest total) and the time when that peak occurred.
Formats include weeks, days, hours, minutes, and seconds. Not all systems
report a peak value, which means this field may not display in output.
|
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free list
|
Number of
available or unallocated buffers in that pool.
|
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min
|
Minimum
number of free or unallocated buffers in the buffer pool.
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max
allowed
|
Maximum
number of free or unallocated buffers in the buffer pool.
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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.
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permanent
|
Number of
these buffers that are permanent.
|
|
free list
|
Number of
available or unallocated buffers in that pool.
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|
min
|
Minimum
number of free or unallocated buffers in the buffer pool.
|
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max
allowed
|
Maximum
number of free or unallocated buffers in the buffer pool.
|
|
hits
|
Count of
successful attempts to allocate a buffer when needed.
|
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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.
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max cache
size
|
Maximum
number of buffers from the pool of that interface that can be in the buffer
pool cache of that interface. Each interface buffer pool has its own cache.
These are not additional to the permanent buffers; they come from the buffer
pools of the interface. 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 times a buffer creation failed. The failure may have occurred because
of a number of different reasons, such as low processor memory, low IOMEM, or
no buffers in the pool when called from interrupt context.
|
|
no memory
|
Number of
times there has been low memory during buffer creation. Low or no memory during
buffer creation may not necessarily mean that buffer creation failed; memory
can be obtained from an alternate resource such as a fallback pool.
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Examples
The following is
sample output from the
show
buffers command using a Cisco IOS Modularity image
from Cisco IOS Release 12.2(18)SXF4 and later releases. Two new output fields
were introduced--Public buffer heads and Temporary buffer heads--and are shown
within comments in the following sample output.
Router# show buffers
Buffer elements:
500 in free list (500 max allowed)
106586 hits, 0 misses, 0 created
Public buffer pools:
Small buffers, 104 bytes (total 50, permanent 50, peak 54 @ 1d13h):
49 in free list (20 min, 150 max allowed)
54486 hits, 0 misses, 4 trims, 4 created
0 failures (0 no memory)
Middle buffers, 600 bytes (total 25, permanent 25, peak 27 @ 1d13h):
25 in free list (10 min, 150 max allowed)
20 hits, 0 misses, 2 trims, 2 created
0 failures (0 no memory)
Big buffers, 1536 bytes (total 50, permanent 50):
50 in free list (40 min, 150 max allowed)
6 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
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
0 failures (0 no memory)
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
0 failures (0 no memory)
Huge buffers, 18024 bytes (total 1, permanent 0, peak 1 @ 1d13h):
0 in free list (0 min, 4 max allowed)
1 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
! Start of Cisco IOS Software Modularity fields
Public buffer headers:
Header buffers, 880 bytes (total 1000, peak 142 @ 1d13h):
864 in permanent free list
142 hits, 0 misses
Temporary buffer headers:
Header buffers, 896 bytes (total 0):
0 in free list
0 hits, 0 misses, 0 trims, 0 created
0 failures
! End of Cisco IOS Software Modularity fields
Interface buffer pools:
Logger Pool buffers, 600 bytes (total 150, permanent 150):
150 in free list (150 min, 150 max allowed)
22 hits, 0 misses
The table below
describes the significant fields shown in the display that are different from
the fields in the first table.
Table 14. show buffers (Cisco IOS Software Modularity) Field Descriptions
|
Field
|
Description
|
|
Public
Buffer Headers
|
|
Header
buffers
|
Buffers
that are 880 bytes long.
|
|
total
|
Total
number of this type of buffer.
|
|
permanent
free list
|
Number of
available or unallocated permanent header buffers.
|
|
hits
|
Count of
successful attempts to allocate a header buffer when needed.
|
|
misses
|
Count of
buffer allocation attempts that resulted in growing the buffer pool in order to
allocate a buffer.
|
|
Temporary
Buffer Headers
|
|
Header
buffers
|
Buffers
that are 896 bytes long.
|
|
total
|
Total
number of this type of buffer.
|
|
free list
|
Number of
available or unallocated header buffers in that 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.
|
|
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.
|
Examples
The following is
sample output from the
show
buffers command on a Cisco Catalyst 4500e switch,
using a Cisco IOS image from Cisco IOS XE Release 3.1.0.SG and later releases.
PDS Public buffers and Packet information was added--and are shown within
comments in the following sample output.
Switch#show buffers
PDS public buffers
Public buffer pools:
Packet buffer, 2048 bytes (total 1000, permanent 1000):
1000 in free list (1000 max allowed)
Header pools:
Packet Header Memory, 0 bytes (total 0, permanent 0):
0 in free list (0 max allowed)
Buffer Header Memory, 0 bytes (total 0, permanent 0):
0 in free list (0 max allowed)
IOSd private buffers:
Buffer elements:
354 in free list (500 max allowed)
27134 hits, 0 misses, 500 created
Public buffer pools:
Small buffers, 104 bytes (total 134, permanent 50, peak 134 @ 01:04:39):
134 in free list (20 min, 150 max allowed)
2554 hits, 28 misses, 0 trims, 84 created
0 failures (0 no memory)
Middle buffers, 600 bytes (total 52, permanent 25, peak 52 @ 01:04:39):
52 in free list (10 min, 150 max allowed)
61 hits, 9 misses, 0 trims, 27 created
0 failures (0 no memory)
Big buffers, 1536 bytes (total 50, permanent 50):
50 in free list (5 min, 150 max allowed)
157 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
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
0 failures (0 no memory)
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
0 failures (0 no memory)
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
0 failures (0 no memory)
Interface buffer pools:
CF Small buffers, 104 bytes (total 100, permanent 100):
100 in free list (100 min, 200 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
BIPC small buffers, 128 bytes (total 250, permanent 250):
250 in free list (250 min, 250 max allowed)
92 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
BIPC middle buffers, 600 bytes (total 300, permanent 300):
300 in free list (300 min, 300 max allowed)
36 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
CF Middle buffers, 600 bytes (total 100, permanent 100):
100 in free list (100 min, 200 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
Syslog ED Pool buffers, 600 bytes (total 132, permanent 132):
131 in free list (132 min, 132 max allowed)
5 hits, 0 misses
CF Big buffers, 1536 bytes (total 25, permanent 25):
25 in free list (25 min, 50 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
BIPC buffers, 4096 bytes (total 2, permanent 2):
2 in free list (1 min, 8 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
IPC Emergency buffers, 4096 bytes (total 301, permanent 300, peak 302 @ 01:05:07):
301 in free list (300 min, 300 max allowed)
39 hits, 1 fallbacks, 66 trims, 67 created
0 failures (0 no memory)
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
CF VeryBig buffers, 4520 bytes (total 2, permanent 2):
2 in free list (2 min, 4 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
CF Large buffers, 5024 bytes (total 1, permanent 1):
1 in free list (1 min, 2 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
BIPC Medium buffers, 16384 bytes (total 5, permanent 5):
5 in free list (5 min, 5 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
BIPC Large buffers, 65535 bytes (total 2, permanent 2):
2 in free list (2 min, 2 max allowed)
0 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
IPC small buffers, 128 bytes (total 250, permanent 250):
228 in free list (250 min, 250 max allowed)
124 hits, 0 fallbacks
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
IPC middle buffers, 600 bytes (total 200, permanent 200):
200 in free list (200 min, 200 max allowed)
293 hits, 0 fallbacks
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
IPC buffers, 4096 bytes (total 300, permanent 300):
298 in free list (300 min, 300 max allowed)
72 hits, 0 fallbacks
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
IPC Medium buffers, 16384 bytes (total 30, permanent 30):
30 in free list (30 min, 30 max allowed)
100 hits, 0 fallbacks
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
IPC Large buffers, 65535 bytes (total 13, permanent 13):
11 in free list (13 min, 13 max allowed)
19 hits, 0 misses
0 max cache size, 0 in cache
0 hits in cache, 0 misses in cache
Header pools:
Catalyst 4000 buffers, 0 bytes (total 14600, permanent 14600):
14600 in free list (0 min, 14601 max allowed)
14600 hits, 0 misses, 0 trims, 0 created
0 failures (0 no memory)
Switch#
The following is
sample shows how to run the
show
buffers
detailed command on a Cisco Catalyst 4500e switch,
using a Cisco IOS image from Cisco IOS XE Release 3.1.0.SG and later releases
and the various keywords and arguments (Explained in the Syntax Description
Table) available.
Switch#
Switch#show buffers ?
detailed Show detailed buffer statistics
| Output modifiers
<cr>
Switch#show buffers detailed ?
process Show detailed process buffer info
Switch#show buffers detailed process ?
iosd IOSd Process
Switch#show buffers detailed process iosd ?
address Buffer at a given address
all All buffers
assigned Buffers in use
failures Buffer allocation failures
free Buffers available for use
input-interface Buffers assigned to an input interface
old Buffers older than one minute
pool Buffers in a specified pool
| Output modifiers
<cr>