Juniper Warning Boot from Backup after corruption primary root partition and Auto recovery

Juniper Warning Boot from Backup after corruption primary root partition and Auto recovery



*** When we loging to any Juniper Router / Switch if this shows like bellow....

THIS DEVICE HAS BOOTED FROM THE BACKUP JUNOS IMAGE


***********************************************************************
**                                                                   **
**  WARNING: THIS DEVICE HAS BOOTED FROM THE BACKUP JUNOS IMAGE      **
**                                                                   **
**  It is possible that the primary copy of JUNOS failed to boot up  **
**  properly, and so this device has booted from the backup copy.    **
**                                                                   **
**  Please re-install JUNOS to recover the primary copy in case      **
**  it has been corrupted.                                           **
**                                                                   **
***********************************************************************


### Solutions ####
##################


* Check Alarms by bellow command

## show chassis alarms

2 alarms currently active
Alarm time               Class  Description
2015-07-10 21:09:58 UTC  Major  PEM 1 Output Failure
2015-07-10 21:09:53 UTC  Minor  Host 0 Boot from backup root



* Now check partitions by bellow command

### show system storage partitions

Boot Media: internal (ad0)
Active Partition: ad0s1a
Backup Partition: ad0s2a
Currently booted from: backup (ad0s2a)

Partitions information:
  Partition  Size   Mountpoint
  s1a        619M   altroot
  s2a        620M   /      
  s3e        49M    /config
  s3f        615M   /var    
  s4a        54M    recovery
  s4e        5.6M


* We can repair the primary partition, by using "request system snapshot media internal slice alternate" without any downtime.

** Copy from backup to Active partition (Also Format Primary Active Partition) by bellow command
### request system snapshot media internal slice alternate

Formatting alternate root (/dev/ad0s1a)...
Copying '/dev/ad0s2a' to '/dev/ad0s1a' .. (this may take a few minutes)
The following filesystems were archived: /


* The following commands are issued to verify the Junos image installed on each slice:

        ###show system snapshot media internal slice 1
        ###show system snapshot media internal slice 2

** againg see alarms by ## show chassis alarms 

** To avoid alarms, use the following command to ensure that the switch boots from the primary partition:

## For EX2200 Switch **  request system reboot slice alternate media internal

### request system reboot slice alternate media internal
*N.B. to reboot now and show the effect  ## request system reboot

** after reboot check Currently booted from:  active or backup ?? if active then ok....
## show system storage partitions          
Boot Media: internal (ad0)
Active Partition: ad0s1a
Backup Partition: ad0s2a
Currently booted from: active (ad0s1a)


** Use auto recovery for some Juniper devices like SRX
### request system autorecovery state save