In Junos, the "var" partition typically refers to the partition where volatile system files, such as logs and temporary files, are stored. It's often a separate partition from the main system partition to prevent these volatile files from filling up valuable space on the primary storage or affecting system stability.

The purpose of the "var" partition is to keep these temporary files isolated from critical system files and configurations. This separation helps in maintaining system stability and performance by ensuring that the core system files are not affected by any issues arising from the volatile files stored in the "var" partition.


When there are more log files or temporary files the /var storage gets full triggering to the alarm REx  /var partition usage high. 

To check which files are taking more space one can run the below command and delete it one by one if the files are taking more space.


root@router> request system storage cleanup dry-run 

List of files to delete:

         Size Date         Name
 149.8K May 31 05:04 /var/log/chassisd.0.gz
 149.8K May 30 12:46 /var/log/chassisd.1.gz
 149.8K May 29 20:27 /var/log/chassisd.2.gz
 150.0K May 29 04:09 /var/log/chassisd.3.gz
 149.8K May 28 11:50 /var/log/chassisd.4.gz
 149.7K May 27 19:32 /var/log/chassisd.5.gz
 150.0K May 27 03:14 /var/log/chassisd.6.gz
 149.8K May 26 10:55 /var/log/chassisd.7.gz
 149.6K May 25 18:37 /var/log/chassisd.8.gz
  21.0K Jan 26 12:29 /var/log/dcd.0.gz
  33.8K Mar 29 14:36 /var/log/irsd.trace.0.gz
  35.1K Mar 29 05:57 /var/log/irsd.trace.1.gz
    27B May 20 12:03 /var/log/wtmp.0.gz
    27B Oct 15  2023 /var/log/wtmp.1.gz
    27B Sep 14  2023 /var/log/wtmp.2.gz
    27B Sep 14  2023 /var/log/wtmp.3.gz
     0B Sep 14  2023 /var/tmp/LOCK_FILE
    11B May  3 02:15 /var/tmp/alarmd.ts
    57B Oct 15  2023 /var/tmp/krt_rpf_filter.txt
     0B Mar  6 10:15 /var/tmp/netproxy  
   111B Sep 14  2023 /var/tmp/pfe_debug_commands
 162.3K Apr 19 12:41 /var/tmp/pfe_debug_info_FPC0.0
 165.3K Apr 19 12:51 /var/tmp/pfe_debug_info_FPC0.1
 165.3K Apr 19 13:00 /var/tmp/pfe_debug_info_FPC0.2
 165.1K Apr 19 13:11 /var/tmp/pfe_debug_info_FPC0.3
 165.3K Apr 19 14:04 /var/tmp/pfe_debug_info_FPC0.4
     0B Oct 15  2023 /var/tmp/rtsdb/if-rtsdb
  38.4M Mar  6 10:15 /var/tmp/shmlog_lock_holder.pid16048.lock

If all the files are of old and no use, one can clean up the log and temporary files using the "request system storage cleanup dry-run".

From the shell, one can use the below command to check the folders which are taking up more space. 


>start shell user root
root@jtac-ptx1000-r2009:~ # pwd >>>> check the current working directory
/root
root@jtac-ptx1000-r2009:~ # cd ..
root@jtac-ptx1000-r2009:/ # cd var >>>>>> move to var folder using the cd command
root@jtac-ptx1000-r2009:/var #  du -cks * | sort -rn  >>>>>>> sort the files using size.
2769520 total
2643820 home
113116  rundb
7680    log
2624    host
2064    db
48      opt
28      pdb
24      platform-config
20      tmp
20      tftpboot
20      jails


Files which take more space can be deleted. However please confirm if the files are not critical or junk files.