Directories on the Router

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

• /config—This directory is located on the primary boot device, that is, on the drive from which the router booted (generally the flash disk, 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 secure shell (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 path name.
• /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 the current core file (0) and the four previous core files, which are numbered 1 through 4 (from newest to oldest).

• /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 flash disk and /altroot is on the hard drive.
• /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 flash disk and /altconfig is on the hard drive.

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