Switch NVRAM no space

Today I encountered very strange error while trying to save switch configuration:

Switch#wr Building configuration... % Warning: Saving this config to nvram may corrupt any network management or security files stored at the end of nvram. Continue? [no]: % Configuration buffer full, can't add command: ntp clock-period 36028830 %Aborting Save. Compress the config.[OK]

This error indicate that there is no free space on the NVRAM for saving the running-configuration into the startup configuration, as you may recall the nonvolatile random-access memory (NVRAM) is an EEPROM chip which holds the startup configuration file and retains content when router is powered down or restarted.

In order to view the contents of the NVRAM just type:

Switch#dir nvram: Directory of nvram:/    36  -rw-       20748                    <no date>  startup-config    37  ----        6592                    <no date>  private-config     1  -rw-         657                    <no date>  IL-SW-UC-2H-#3801.cer 65536 bytes total (37120 bytes free)

As you can see there is only 37KB free on the NVRAM and my configuration weight a little bit more:

Switch#sh running-config Building configuration... Current configuration : 38563 bytes ! ! Last configuration change at 14:27:26 gmt Sun Jun 8 2014 by xxx ! NVRAM config last updated at 14:28:46 gmt Sun Jun 8 2014 by xxx ! version 12.2 service nagle no service pad service tcp-keepalives-in <OUTPUT OMMITED>

There is an option to use service compress-configuration which will compress the startup configuration but it’s valid only for higher series switches (such as the 45xx and 65xx).

On my 2960 switch it will give the following output:

Switch(config)#service compress-config Boot ROMs do not support NVRAM compression. Disabling service compress-config. Switch(config)#

So in order to solve this issue I had to remove some configuration lines from the current configuration, after that I was able to save the running-config to the startup:

Switch#wr Building configuration... [OK]