Technical Documentation
Performing a Recovery Installation on a QFX3500 Switch and QFX3008 Interconnect Device
If Junos OS on your device is damaged in some way that prevents the software from loading correctly, you may need to perform a recovery installation using an emergency boot device (for example, a USB flash drive) to restore the default factory installation. Once you have recovered the software, you need to restore the device configuration. You can either create a new configuration as you did when the device was shipped from the factory, or if you saved the previous configuration, you can simply restore that file to the device.
If at all possible, you should try to perform the following steps before you perform the recovery installation:
- Ensure that you have an emergency boot device to use during the installation.
- Copy the existing configuration in the file /config/juniper.conf.gz from the device to a remote system, such as a server, or to an emergency
boot device. For extra safety, you can also copy the backup configurations
(the files named /config/juniper.conf.n, where n is a number from 0 through
9) to a remote system or to an emergency boot device.
Warning: The recovery installation process completely overwrites the entire contents of the internal flash storage.
- Copy any other stored files to a remote system as desired.
To reinstall Junos OS:
- Insert the emergency boot device into the device.
- Reboot the switch.
Note: Do not power off the device if it is already on.
[edit system]user@switch> request system reboot - When the software prompts you with the following question,
type y:
WARNING: The installation will erase the contents of your disk. Do you wish to continue (y/n)? y
- The device copies the software from the emergency boot
device, occasionally displaying status messages. Copying the software
can take up to 10 minutes.
When the device is finished copying the software, you are presented with the following prompt:
*** Mon Mar 21 21:08:41 UTC 2011 *** Installation successful.. Please select one of the following options: Reboot to installed Junos after removing install media (default) ... 1 Reboot to installed Junos by disabling install media ............... 2 Exit to installer debug shell ...................................... 3 Install Junos to alternate slice ................................... 4 Your choice: 4 NOTE: System installer will now install Junos to alternate slice Do not power off or remove the external installer media or interrupt the installation mechanism.
- Select 4 to install Junos OS to the alternate slice of the partition, and then press Enter.
- Remove the emergency boot device when prompted and then press Enter. The device then reboots from the internal flash storage on which the software was just installed. When the reboot is complete, the device displays the login prompt.
- Create a new configuration as you did when the device was shipped from the factory, or restore the previously saved configuration file to the device.
