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Upgrade switch stacks 3750G - Auto Tar. Twice size needed? or NOT?

Hi All,

I have a switch of 6 stacks that needs upgrade.

Switch   Ports  Model           
------   -----  -----            
     1   12     WS-C3750G-12S
     2   12     WS-C3750G-12S
     3   24     WS-C3750G-24T 
     4   24     WS-C3750G-24T
     5   24     WS-C3750G-24T
*    6   24     WS-C3750G-24T

     Size(b)     Free(b)      Type  Flags  Prefixes
*   15998976     7957504     flash         rw   flash: flash6:
    15998976     7944192   unknown     rw   flash2:
    15998976     7957504   unknown     rw   flash3:
    15998976     7957504   unknown     rw   flash5:
    15998976     7957504   unknown     rw   flash1:
    15998976     7957504   unknown     rw   flash4:

It looks like system came with bout ~22MB of total flash. And im left with only ~7mb of free space

Tar file that i am upgrading to c3750-ipserviceslmk9-tar.122-55.SE8.tar = 13.5mb

Based on the cisco upgrade stack documentation - for Manual (.tar image) method

"You need to make sure you have sufficient space available in the Flash of the master switch. The master switch should have twice the amount of space of the .tar image file size. This space is needed to store the .tar file as well as to store the content of the .tar file that you extract in step 2. For example, if the .tar image size is 10 Mb, you need to have a minimum of 20 Mb of free space."

So to say, even if i were to remove the existing IOS, i won;t be able to get 2x the space need for my tar.


My bigger question is:- Based on the automatic (.tar image) method. IT DOES NOT require me to have the 2x space?

Is that correct? im asking because cisco doc does not quote the statement under automatic tar method

So do i just use the command 'archive download-sw /overwrite'


Please advise, as this is crucial. Any error would mean company network outage for the longest period of time, as this is their core switch.





Hall of Fame Super Gold

Use the "/overwrite" command.

Use the "/overwrite" command.  


So the command will go like this:  archive download-sw /overwrite tftp://<TFTP IP address>/IOS.tar". 


Use 12.2(55)SE9 as it's more "refined".

Community Member

hi,Yes ill be using 12.2(55


Yes ill be using 12.2(55)SE9

Then again, is it alright for me to use the automatic .tar method without the sufficient "Twice" flash space for tar extraction?



Hall of Fame Super Gold

Then again, is it alright for

Then again, is it alright for me to use the automatic .tar method without the sufficient "Twice" flash space for tar extraction?

Permit me to provide you with MY honest opinion.


The switches in your stack, all of them, do NOT have any room to store two or more complete IOS.  So you will need to use the automated "archive download-sw" to completely install the IOS.  In order for your IOS to be loaded correctly, you use the "/overwrite" option.  This means the IOS will be loaded into the switch's RAM, the old IOS deleted and the RAM contents (of the IOS) gets "off loaded" to the switch's flash memory. 


Be aware that you have five switches in a stack, therefore you also need to use the "/destination <switch number>" or the IOS will only be loaded into the active switch member.  The complete command would look something like this: 


archive download-sw /overwrite /destination 1 /dest 2 /dest 3 /dest 4 /dest 5 tftp://<TFTP IP address>/IOS.tar

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