Error opening nvram:/startup-config (Read-only file system) – Cisco ASA

Recently, I have encountered an issue where my virtual ASA couldn’t write memory (copy running-configuration startup-configuration).

asav/pri/act(config)# wr
Building configuration...
Cryptochecksum: b3d790bf 1f8ae83c b72965aa 295bb863

%Error opening nvram:/startup-config (Read-only file system)

After researching on the possible fix, I have found two solutions worth mentioning. Please note they did not work for me, but your case could be different so read on!

First solution talks about Cisco Bug CSCvc6249 where in a nutshell you may have to upgrade the firmware if you are running on one of these versions:

Second solution which I found on routerfreak blog talks about doing a check on your physical disk for corruption. Two commands that you can run are as follow:
fsck disk0

fsck flash
Problem with virtual ASA is that second solution will throw the following error:
asav/pri/act# fsck disk0
WARNING: Unmount FWH secure store failed. fsck can not continue.
Type help or '?' for a list of available commands.
To understand the problem better I’ve reached out to my friends at Cisco with the following recommendation:

From what I can see in other similar tickets a reboot may resolve the issue, if it doesn’t then the only other option would be to build a new ASAv. I suggest you take a backup of this appliance beforehand either via ASDM or by using ‘more system:running-config’.

Caveat with virtual appliances is that they grab storage from the compute pool and there is a possibility that something happened at the underlay layer which you don’t have control over such as simple VMware vMotion.

If you are running virtual hopefully you have HA pair because you may lose the data during the reboot. My suggestion would be to either spin up quick ha to sync the data and failover before the reload or in the worst case backup your config with using ‘more system:running-config’ command

Bottom line, in my case reload did fix Error opening nvram:/startup-config issue.

And that is it, I hope you find this informative and good luck.


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