Directories on the Router

JUNOS software files are stored in the following directories on the router:

• /altconfig—When you back up the currently running and active file system partitions on the router to standby partitions using the request system snapshot command, the /config directory is backed up to /altconfig. Normally, the /config directory is on the CompactFlash card and /altconfig is on the hard disk.
• /altroot—When you back up the currently running and active file system partitions on the router to standby partitions using the request system snapshot command, the root file system (/) is backed up to /altroot. Normally, the root directory is on the CompactFlash card and /altroot is on the hard disk.
• /config—This directory is located on the primary boot device, that is, on the from which the router booted (generally the CompactFlash card, device wd0). This directory contains the current operational router configuration and the last three committed configurations, in the files juniper.conf, juniper.conf.1, juniper.conf.2, and juniper.conf.3, respectively.
• /var—This directory is always located on the hard disk (device wd2). It contains the following subdirectories:
  • /var/home—Contains users’ home directories, which are created when you create user access accounts. For users using SSH authentication, their .ssh file, which contains their SSH key, is placed in their home directory. When a user saves or loads a configuration file, that file is loaded from their home directory unless the user specifies a full pathname.
  • /var/db/config—Up to six additional previous versions of committed configurations, which are stored in the files juniper.conf.4 through juniper.conf.9.
  • /var/log—Contains system log and tracing files.
  • /var/tmp—Contains core files. The software saves up to five core files, numbered from 0 through 4. File number 0 is the oldest core file and file number 4 is the newest core file. To preserve the oldest core files, the software overwrites the newest core file, number 4, with any subsequent core file.

Each router ships with removable media (device wfd0) that contains a backup copy of the JUNOS software.