Why SW-3850 loses config after reload even though config is saved?

[Gabe Rivas]

Configuration is saved on 3850 switch and it loses everything when it is reloaded. There is no signs of hardware failure as far as I can tell

[mbarnovsky1]

Hi Gaberivas,

Have you checked the configuration register value? I know values such as 0x2142 will ignore the contents of NVRAM.

- Marcus

[Gabe Rivas]

Hi nbarnovsky1,

I do not believe switches use configuration register like routers do, at least not the 3850 switches. There is a boot variable that you can change for that so instead of using NVRAM it uses another memory to read saved configurations but I checked that and the variable is at its default setting, which reads configuration files from the NVRAM. I have tested this by issuing "copy running-config startupconfig" and then "show startup" to make sure configuration was saved. After a reload all is gone...

[hcmitchell1]

Thanks, This was my issue

[Richard Primm · Accepted solution]

Hi Gaberivas,

I cannot be 100% sure, however we see this issue every now and then on the 3850 and its due to one simple thing.  If you are using a ethernet jack with a "boot" on it in port 1, it very likely is resting on the "reset button."  The cable boot is making extended contact with the mode button resulting in Express Setup being invoked. The following messages are seen when this issue is encountered on the WS-3850-48 or other IOS-XE based switch:

##########################
%SYS-7-NV_BLOCK_INIT: Initialized the geometry of nvram
%EXPRESS_SETUP-6-CONFIG_IS_RESET: The configuration is reset and the system will now reboot
%SYS-5-RELOAD: Reload requested by NGWC led process. Reload Reason: Reload command.
%STACKMGR-1-RELOAD_REQUEST: 1 stack-mgr: Received reload request for all switches, reason Reload command 
%STACKMGR-1-RELOAD: 1 stack-mgr: Reloading due to reason Reload command 
##########################  

There is an easy workaround to prevent this:

Disable Express Setup with the following command:
# config t
#(config) no setup express

Or remove the the cable boot from the cable installed in port 1.

Field Notice:  http://www-tac.cisco.com/Support_Library/field_alerts/fn63697.html

HTH

Luke

[Ahmad Fayaz Alizad]

Gaberivas, I did what you told but i didn't get result, still my 3850 switch after reloading loosing all of it's configuration.

[Fabian Donvil]

I just recently had this problem too of config erasing after reload even though i had saved my config both through write mem and copy run start. i'm going to put this here for the sake of completeness.

Turns out that the config-register parameter from the bootvariables was set to 0x2142. which boots everything normally but completely ignores config. only thing pointing this out was one line in the reload.

you can easily check this via "show bootvar" in exec

and set it to (for example) 0x2102 by "config-register 2102" in config mode

[tribelion777]

This was very helpful.  My configuration was not set to 0x2102.  After changing it to 0x2102 I reloaded and it came back up with the correct configuration.  Thank you.

[Arunagiri Nallusamy · Accepted solution]

Hi Gaberivas,

Could you check what is the current value of the configuration-register? Does it look like Configuration register is 0x142 (will be 0x102 at next reload).

++ If so, this is a known software caveat documented in Bug: CSCui51930 and also in Bug: CSCui54490. These bugs haven been fixed yet, but, there is a permanent work around in place. The configuration-register value needs to be 0x102.

++ Boot the switch into ROMMON mode.
++ Check if the SWITCH_IGNORE_STARTUP_CFG bit is set to 1 using the set command.
++ Issue the command unset SWITCH_IGNORE_STARTUP_CFG so as to include the STARTUP config
contents when it boots up.

++ Then, boot the switch up and check if the issue is resolved. I have seen this in multiple customer cases and this has caused the issue almost every time.

Thanks,

Arun

[johnwenhuang]

this is really helpful

[SAJAL17]

Thanks a lot, very helpful. Solved my problem.

[Ahmad Fayaz Alizad]

Thanks #Gaberivas, Your Right.

[imanioscar]

This worked for me , the switch now saves configuration even after reboot

[Gabe Rivas]

After looking at the switch logs, I was able to see the switch has had "Express Setup" activated. Even though the suggestion by Luke makes sense, there was no cable with the cover thing pressing the mode button so I believe someone might have pressed it.

Thanks

[paragr555]

If Any CISCO Device not saving the config:

The Solution:

# config ternminal
no setup express
service compress-config
config-register 2102

Boot into rommon (rommon is when you interrupt the boot loader and get to the Switch prompt and run the flash_init command) and remove the boot variable that is set to ignore the startup config.

Boot into ROMMON mode
Connect to the console of the switch
Power off the switch
While holding the MODE button down, restore power to the switch
Keep pressing the MODE button and watch the console output
After approx. 10-15 seconds, the switch should end up at the ROMMON/boot loader switch: prompt
Release the MODE button
Type command flash_init
Type command set
Look for if SWITCH_IGNORE_STARTUP_CFG bit is set to 1
Type command unset SWITCH_IGNORE_STARTUP_CFG
Reload the switch

Example set output:

ABNORMAL_RESET_COUNT=0
ASIC_PCI_RESET=1
BOOT=flash:packages.conf
BOOT_LOADER_UPGRADE_DISABLE=1
BSI=0
CFG_MODEL_NUM=WS-C3850-48P-S
CLEI_CODE_NUMBER=IPM8E00ARB
CSR_PCIERST_DISCONNECTED=yes
DC_COPY=yes
D_STACK_DOMAIN_NUM=1
ECI_CODE_NUMBER=468919
LICENSE_BOOT_LEVEL=ipbasek9,all:ngwc;
MAC_ADDR=00:EB:D5:94:72:80
MANUAL_BOOT=no
MODEL_NUM=WS-C3850-48P
MODEL_REVISION_NUM=AA0
MOTHERBOARD_ASSEMBLY_NUM=73-15800-07
MOTHERBOARD_REVISION_NUM=B0
MOTHERBOARD_SERIAL_NUM=FOC202114XB
POE1_ASSEMBLY_NUM=73-16439-01
POE1_REVISION_NUM=A0
POE1_SERIAL_NUM=FOC202071F2
POE2_ASSEMBLY_NUM=73-16439-01
POE2_REVISION_NUM=A0
POE2_SERIAL_NUM=FOC202071CT
RANDOM_NUM=966545832
RECOVERY_BUNDLE=sda9:cat3k_caa-recovery.bin
STKPWR_ASSEMBLY_NUM=73-11956-08
STKPWR_REVISION_NUM=B0
STKPWR_SERIAL_NUM=FOC20216XC4
SWITCH_IGNORE_STARTUP_CFG=1 <<<<<<< This Boot variable means every time the
SWITCH_NUMBER=1 switch reboots to ignore the config in NVRAM
SYSTEM_SERIAL_NUM=FCW2021C1US
TAN_NUM=800-43041-02
TAN_REVISION_NUMBER=C0
TEMPLATE=advanced
TERMLINES=0
USB_ASSEMBLY_NUM=73-16576-01
USB_REVISION_NUM=A0
USB_SERIAL_NUM=FOC20212NWT
VERSION_ID=V06

unset SWITCH_IGNORE_STARTUP_CFG=1 <<<<<<<<<< unset the bootvar and reload

Alternatively, according to Cisco password recovery documentation, you may also be able to run the command SWITCH_IGNORE_STARTUP_CFG=0