Cisco 2921 IOS

[cyanesh]

Hello,

I have a couple of questions about a Cisco 2921 I am using as a DMVPN hub.

1.  I am trying to upgrade the IOS and have attempted to free up space, but the space free hasn't changed.  It still shows not enough bytes free, and the space didn't free up.  General consensus seems to be the flash needs to be reformatted.  Would you concur?  

2.  If the flash needs to be formatted, it looks like this can be hot.  I have never personally formatted a routers flash hot.  But the config is NVRAM, the CA cert and CRL's are NVRAM as well.  Since IOS is loaded in memory and is running, I should be able to format the flash, then copy the IOS I want back onto the newly formatted flash.  Would you concur with that?  

3.  If I were to format the flash, I have backed up the CA.crl file and the .p12 cert for the DMVPN.  Since they are stored in NVRAM, do I really need to copy back?  Or are there any other LIMFACs dealing with the DMVPN side of things?

4.  Are there any other gotcha's that may be lurking?  I have the config file backed up.  The DMVPN certs make me a little nervous.  

Thanks for any input,

Chris

[Georg Pauwen · Accepted solution]

Hello,

when you copy from TFTP to flash, the system should prompt you and ask you if you want to erase the flash. Anything in NVRAM will not be affected, so you can erase the flash (and subsequently the current IOS).

That said, backing up the current config is always recommended.

[cyanesh]

Georg,

Thanks for the reply.  I don't ever remember IOS asking me if I want to format the flash first when copying from TFTP.  In this particular case, it tries to copy and then gives me an error about not enough free space.   Thank you for confirming about NVRAM.  What do you think about certificates? While I do have them backed up, I am wondering if just having them in NVRAM is sufficient?  

[Georg Pauwen · Accepted solution]

Hello,

anything you can back up, back it up, if only for the sake of having an additional copy in case of a hardware failure.

NVRAM content is not affected. When you do 'copy tftp: flash' does your sequence look like this example ?

http://www.cisco.com/c/en/us/support/docs/routers/3800-series-integrated-services-routers/49044-sw-upgrade-proc-ram.html#example1

[cyanesh]

Georg,

No, I don't get presented the option to erase file system.  I just get an error copying (not enough space).  Which makes me wonder...is the flash bad or does it need to be reformatted?  The files used on flash with the show flash: don't add up to the space being reported as used.  

[Georg Pauwen]

Hello,

can you try and manually erase the flash?

[cyanesh]

I haven't yet.  I could.  Being that this is a very important router, I was feeling out the implications with erasing the flash to upload a new IOS.  Seems there would be little risk while it's operating to erase the flash and load the IOS I want.  The configs I have.  The DMVPN certs was a concern.  Would the best way be to issue the format flash0: or to use copy /erase tftp://<ios> ?  

[cyanesh]

Ok, I did try the copy /erase command and here is the results below:

Destination filename [c2900-universalk9-mz.SPA.155-3.M5.bin]?
Accessing ftp://10.10.50.160/Staging/c2900-universalk9-mz.SPA.155-3.M5.bin...
%Warning:Filesystem <flash0> does not support erase operation
Loading Staging/c2900-universalk9-mz.SPA.155-3.M5.bin !
%Error copying ftp://10.10.50.160/Staging/c2900-universalk9-mz.SPA.155-3.M5.bin (Not enough space on device)

[Leo Laohoo]

1.  I am trying to upgrade the IOS and have attempted to free up space, but the space free hasn't changed.  It still shows not enough bytes free, and the space didn't free up.  General consensus seems to be the flash needs to be reformatted.  Would you concur?  

2921 has TWO (2) CF flash ports at the back.  By default, port 0 is always loaded with a CF but port 1 can be optionally loaded with CF.  

Check to see if there is a CF in port 1 with the command "dir flash1:".

[cyanesh]

Leo,

No, only flash0:.  One of the first things I checked.  

[Leo Laohoo]

Ok, so I present THREE (3) options: 

1.  Eject the CF in Flash0: and copy the IOS from your PC to the CF (directly) using a multi-media card reader.  

2.  Go to your favorite electronics shop and find a CF (maximum size 16 Gb) and hope-and-see if the router supports it.  If not, find another one that is supported by the router.  You'll thank yourself for installing a 2nd CF. 

3.  See those USB slots?  Guess what they are for?  Same rules:  Must be supported by the router and maximum size is 16 Gb.  

When using third party CF and USB thumb drives make sure you format them using the router before putting any IOS files into them. 

[cyanesh]

In the end, I ended up reformatting the flash.  Turned out to be a non-issue as far as that goes.  Still don't know why the free space never changed after deleting some files, but the format took care of it.  Thanks for all the inputs.

Chris