ENVIRONMENT:

1，juniper ex2200（11.4R7.5）

SYMPTOMS:

1，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.

1，improperly shutdown

SOLUTION:

1admin> show system storage partitions
Boot Media: internal (da0)
Active Partition: da0s2a
Backup Partition: da0s1a
Currently booted from: backup (da0s1a)

Partitions information:
  Partition  Size   Mountpoint
  s1a        183M   /         
  s2a        184M   altroot   
  s3d        369M   /var/tmp  
  s3e        123M   /var      
  s4d        62M    /config  

2，admin@ex2200> request system snapshot slice alternate
Formatting alternate root (/dev/da0s2a)...
Copying '/dev/da0s1a' to '/dev/da0s2a' .. (this may take a few minutes)
The following filesystems were archived: /

3，request system reboot slice alternate media internal   
Reboot the system ? [yes,no] (no) yes

1，

Summary:

1，