386.10 - "Your router is running low on free NVRAM"

[choleric]

Before I start troubleshooting in earnest: Is "Your router is running low on free NVRAM" a known issue on Merlin 386.10 (at least for the RT-AC68U)?

 

[alecmascot]

There have been several recent posts you might want to look at.

 

[choleric]

In any case, I just ran:

for line in `nvram show | grep ^[^=]*=$ `; do var=${line%*=}; nvram unset $var; done; nvram commit

...and it took me from 62,880 to 52,322 bytes, and the warning has gone away. God knows if this status will survive a reboot.

 

[automaton]

Yes I went from 386.5_2 today to 386.10 and there's a big jump.

Here it is before the upgrade:

admin@RT-AC68U-MAIN:/tmp/home/root# nvram show | awk '{print length(), $0 | "sort -n -r"}' | cut -d"=" -f 1 | head -n 20
size: 47827 bytes (17709 left)
931 nc_setting_conf
573 rc_support
571 dhcp_staticlist
164 subnet_rulelist
153 asus_device_list
131 wl1_chansps
129 wps_env_buf
128 vpn_serverx_clientlist
120 qos_rulelist
112 vlan_rulelist
98 cfg_device_list
92 1a5ga2
92 1a5ga1
92 1a5ga0
89 vpn_server2_ncp_ciphers
89 vpn_server1_ncp_ciphers
89 vpn_client5_ncp_ciphers
89 vpn_client4_ncp_ciphers
89 vpn_client3_ncp_ciphers
89 vpn_client2_ncp_ciphers

And directly after:

admin@RT-AC68U-MAIN:/tmp/home/root# nvram show | awk '{print length(), $0 | "sort -n -r"}' | cut -d"=" -f 1 | head -n 20
size: 59200 bytes (6336 left)
931 nc_setting_conf
573 rc_support
571 dhcp_staticlist
164 subnet_rulelist
153 asus_device_list
131 wl1_chansps
129 wps_env_buf
128 vpn_serverx_clientlist
120 qos_rulelist
112 vlan_rulelist
98 cfg_device_list
92 1a5ga2
92 1a5ga1
92 1a5ga0
89 vpn_server2_ncp_ciphers
89 vpn_server1_ncp_ciphers
89 vpn_client5_ncp_ciphers
89 vpn_client4_ncp_ciphers
89 vpn_client3_ncp_ciphers
89 vpn_client2_ncp_ciphers

Running the command you mentioned above does save some space:

size: 49665 bytes (15871 left)

But it's still significantly increased with no identifiable reason as to why.

 

[bennor]

Before I start troubleshooting in earnest: Is "Your router is running low on free NVRAM" a known issue on Merlin 386.10 (at least for the RT-AC68U)?

Have you done a subforum search? Yes the low NVRAM is a well known and discussed issue with the RT-AC68U. See here, here, and here for example, there are other posts and threads on the issue. I ran into it on the Alpha 386.9, see here. And there are posts in both the Alpha 386.10 and final 386.10 threads, see here and here. RMerlin has explained why this error is appearing in an earlier thread:

Low nvram notification is nothing new, and is becoming increasingly common for that old model as it's running out of nvram space with every new firmware adding new nvram settings. It's part of why Asus is leaving it on the 386 branch most likely, as 388 probably adds even more nvram settings.

This 9 years old model is starting to show its age, with Asus having added lots of new features to it since its initial launch in 2013.

I might have to start considering removing some things from the RT-AC68U to save some nvram space. Reducing the number of OpenVPN clients would be such a thing, as each client consumes around 1 KB of nvram even while not in use.

See this thread for some suggestions on dealing with low NVRAM. Or do a hard factory reset and manually reconfigure without importing a saved router cfg file. Or use YazDHCP if you have a lot of manually reserved IP addresses. Or see this post that has a script to deal with some NVRAM variables. Or see this thread started yesterday that may have more suggestions on how to handle low NVRAM.