Memory Usage

[CSCO11983020]

Hello,

I don't know how can I check the memory usage in my switch 2960S.

I checked with "show version" that the switch has 128 MB of memory. However, I see with "show memory" that the whole total memory between Processor, I/O and Driver is less than 128 MB.

Is the memory split up in more than Processor, I/O and Driver?

Thanks, regards.

[Madhukrishnan Gopinathan Nair · Accepted solution]

Hello ,

The  "total " value under show memory displays the the total amount of memory available after the system image loads and builds its data structures. I think that is why you see it is less than the actual DRAM on switch.

Router>show memory summary 

            Head       Total (b)   Used (b)  Free (b)   Lowest (b)  Largest (b)
Processor   60AB4ED0   5550384     2082996   3467388    3464996     3454608
I/O         40000000   16777216    1937280   14839936   14839936    14838908

Total = the total amount of memory available after the system image loads and builds its data structures.

Used = the amount of memory currently allocated.

Free = the amount of memory currently free.

Lowest = the lowest amount of free memory recorded by the router since it was last booted.

Largest = the largest free memory block currently available.

Hope this helps. Please do remeber to rate all useful posts and mark as "correct answer" if it has answered your question.

Thanks,

Madhu.

[CSCO11983020]

Hello Madhu,

First of all, thanks for the information. It seems that although the switch has 128 MB of DRAM, the memory proccessor has only 64 MB, plus 14 MB of I/O and 1 MB of "Driver te". Therefore, I suppose that the remaining memory is for system image and data structures.

Is there any way or command to know the size of system image and data structures?

Thanks, best regards.

[Madhukrishnan Gopinathan Nair]

Hi ,

You can check the size of the image from the flash (Hoping you are loadin IOS from switch itself and not from network). The command to display flash varies on different platforms. For example on 3750 you can use below.

show flash: 

For bigger switches like 6500 you may to issue

sh bootflash:

sh sup-bootflash: 

etc...

Hope this helps and kindly remember to rate and mark answer which are correct and useful.

Note : I am not sure how to check data structure and don't think we have a command to check it.

Regards,

Madhu.

[Joseph W. Doherty]

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Posting

I believe, by default, many IOS images, on flash, are compressed, and decompressed as loaded into flash.  So, for such images, looking at their file size won't directly reveal their in memory size (however twice the size is probably somewhere in the ballpark).

Some data structure sizes will vary based on usage and configuration, some can also change size dynamically.  I think many of those are accounted for under processor used memory.