Description

This article discusses how to create, verify recovery and non-recovery snapshots on Junos devices.

Solution

A non-recovery snapshot is stored in Junos OS volume used for running the device software and hold the configuration and the logs.

A recovery snapshot stored in OAM (Operations, Administration, and Maintenance) volume holds a full backup that can be used in case something goes wrong with Junos volume

There are two types of snapshots:

Non-Recovery Snapshot:

  •     Resides on the Junos volume.
  •     Points to the current set of packages and configuration at the time when the snapshot was taken.
  •     Multiple non-recovery snapshots can be taken.
  •     They can be renamed.
  •     Can be used to boot from them at the next reboot.

Recovery Snapshot:

  •     Resides on the OAM volume
  •     There can be only one at a time
  •     Can be used to recover the Junos volume
  •     Contains a full copy of the packages and configuration at the time when the snapshot

How to create a non-recovery snapshot 

root@EX34xx> request system snapshot
fpc0:
--------------------------------------------------------------------------
NOTICE: Snapshot snap.20170908.011626 created successfully    >>> Snapshot Created
root@EX34xx>

How to check the list of non-recovery snapshots 

root@EX34xx> show system snapshot
fpc0:
--------------------------------------------------------------------------
Non-recovery snapshots:
Snapshot snap.20170908.011626:
Location: /packages/sets/snap.20170908.011626    <----- Here is the snapshot package
Creation date: Sep  8 01:16:27 2017
Junos version: 15.1X53-D56

How to boot the device from non-recovery snapshot ( /dev/gpt/junos (Junos volume) 

root@EX3400> request system snapshot load snap.20170223.114901
fpc0:
--------------------------------------------------------------------------
NOTICE: Loaded snapshot snap.20170223.114901.   <----- Loading this package
NOTICE: This command requires a reboot to complete the operation.
NOTICE: To cancel this operation, run 'request system software rollback'

How to delete the non-recovery snapshot 

root@EX3400> request system snapshot delete snap.20170223.114901
fpc1:
--------------------------------------------------------------------------
NOTICE: Snapshot 'snap.20170223.114901' deleted successfully

How to create a recovery snapshot 

root@EX34xx> request system snapshot recovery
fpc0:
--------------------------------------------------------------------------
Creating image ...
Compressing image ...
Image size is 243MB
Recovery snapshot created successfully

Recovery snapshot does the same thing as request system snapshot slice alternate on the older platforms of EX series devices.

How to delete recovery snapshot stored in the OAM volume

  1. Mount the OAM partition: 

    root@switch>start shell user root
%mount /dev/gpt/oam /oam
%ls -l /oam/
%cli

  2. Delete the recovery snapshot: 

    %cli

    root@switch>file list /oam/snapshot/

    root@switch>file delete /oam/snapshot/recovery.ufs.uzip

    root@switch>file list /oam/snapshot/
    root@switch>show system snapshot

    You should see an output similar to the following: 

    root@switch> show system snapshot
fpc0:
--------------------------------------------------------------------------
No non-recovery snapshots available on the Junos volume

Recovery Snapshots:
mount: /dev/gpt/oam: Device busy

No recovery snapshots available on the OAM volume   <----- recovery snapshot has been deleted
    [master:0]
root@switch>

  3. Then, unmount the oam partition: 

    root@switch> start shell user root
%umount /dev/gpt/oam

How to recover the OAM volume 

root@EX3400> request system recover oam-volume

NOTICE: Recovering the OAM volume ...
da0p1 deleted
da0p1 added
/dev/gpt/oam: 500.0MB (1024000 sectors) block size 32768, fragment size 4096
    using 4 cylinder groups of 125.03MB, 4001 blks, 16128 inodes.
super-block backups (for fsck_ffs -b #) at:
 192, 256256, 512320, 768384
Verified oam signed by PackageProductionEc_2016 method ECDSA256+SHA256
Installing OAM volume contents ...
The OAM volume is now installed
NOTICE: Creating a recovery snapshot on the OAM volume ...
Creating image ...
Compressing image ...
Image size is 243MB
Recovery snapshot created successfully
NOTICE: OAM volume recovered    <----- Recovered

In case you are unable to create recovery snapshot due to 'ERROR: The OAM volume is too small ' , refer to KB33892 - 'ERROR: The OAM volume is too small to store a snapshot' message while creating a recovery snapshot on RE1800 [juniper.net]

NOTE: Make sure you are running the supported version on the device before attempting to execute the commands. The documents in the Related Links section lists the versions in which this command was introduced.

Modification History

2021-10-14: Updated related links, minor format changes. 
2020-05-15: Updated the Title, Summary, Cause, Solution, and added Products to the list OAM.
2020-07-20: Added ' How to delete recovery snapshot stored in the OAM volume ' section 

Related Information