Memory Utilization Problem

Unanswered Question
Nov 1st, 2006
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I recently upgraded several 3640s from 64MB to 128MB of DRAM. I am experiencing conflicting memory size information from the IOS. "Sho Ver" correctly shows the amount of memory I physically installed on the router:


Processor board ID 26855150

R4700 CPU at 100MHz, Implementation 33, Rev 1.0

1 FastEthernet interface

3 Serial interfaces

DRAM configuration is 64 bits wide with parity disabled.

125K bytes of NVRAM.

32768K bytes of processor board System flash (Read/Write)


Sho mem with IOS version 12.4(5b) shows apx 20mb of DRAM:


TEST#sho mem sum

Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)


Processor 64B762E0 21536032 16139300 5396732 3547360 3013312


I/O 6000000 33554432 2012360 31542072 31542072 3154204


After an IOS upgrade to 12.4(10a)I receive additional conflicting infomration


TEST#sho mem sum

Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)


Processor 64B762E0 21536032 16139300 5396732 3547360 3013312


I/O 6000000 33554432 2012360 31542072 31542072 3154204


Has anyone seen this before? None of the "sho mem" information matches what I physically have in the router. Thanks in advance.

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network.king Wed, 11/01/2006 - 09:18
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Hi


From your logs , both seems to be the same , I think you have pasted the same .


As we know that cisco releases IOS with variuos versions and it includes some new features also . So the older ios might have taken a less memory , but the new ios would have got some new features and will take more memory . So you will always see a difference after the IOS upgrade.


To have a complete calculation of memory use :

show region

and total the values to see if it matches.


Hope it helps.


regards

vanesh k

lgijssel Wed, 11/01/2006 - 09:26
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You indeed have far less memory available than what is installed. I have verified my theory with our 1760 router running CME.

The sum of Total Processor + Total IO equals about 80MB.

In my opion he rest is taken by the program code which is also loaded into RAM. On flash this takes 29MB which could very well be nearly 50MB after decompression. This adds up quite nicely to the 128MB that is actually installed.

I assume that this will also be more or less correct for your system. Are you perhaps running enterprise code?


Regards,

Leo

efairbanks Wed, 11/01/2006 - 11:05
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I am running enterprise code. So "show memory stat" shows memory utilization after system overhead, such as the uncompressed IOS, is excluded? I did a "show region" as suggested above. If I add up IOMEM and Main, I reach a 128MB total, which is correct.


Does anyone know how NMSs obtain info to perform memory utilization calculations? Thanks for all of your help.



Start End Size(b) Class Media Name

0x06000000 0x07FFFFFF 33554432 Iomem R/W iomem

0x30000000 0x31FFFFFF 33554432 Flash R/O flash

0x60000000 0x65FFFFFF 100663296 Local R/W main

0x60009004 0x62A6C06F 44445804 IText R/O main:text

0x62A6E000 0x6475BF7F 30334848 IData R/W main:data

0x6475BF80 0x64B762DF 4301664 IBss R/W main:bss

0x64B762E0 0x65FFFFFF 21536032 Local R/W main:heap

0x80000000 0x85FFFFFF 100663296 Local R/W main:(main_k0)

0xA0000000 0xA5FFFFFF 100663296 Local R/W main:(main_k1)

lgijssel Wed, 11/01/2006 - 11:42
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There will definitely be an SNMP MIB to read the required memory info.


Leo

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