From Junos 9.3 forward, the compact flash requires a minimum of 512 MB, and from Junos 9.0, M-series devices require 1 GB flash. Not having enough free compact flash space available to perform an upgrade is common, especially on routers that have large logs, trace files, or old software packages lying about in users’ home directories. The migration guide provides detailed instructions on how to free up compact flash space to enhance the chances of being able to upgrade to Junos on systems with 256 MB compact flash chips. The instructions have you delete various temporary and unneeded files using combinations of CLI and root shell mode commands, some of which are demonstrated on the following pages.
The limited compact flash storage space, combined with the lack of a hard drive for storing images that are being unpacked for installation, can create problems when you attempt to upgrade or downgrade Junos versions on any Juniper router. The following steps are general approaches to freeing up compact flash space. You will need root access to delete any files that are owned by root.
First, we use the CLI cleanup utility to rid ourselves of the low-hanging fruit:
request system storage cleanupList of files to delete: Size Date Name 11B Apr 17 07:41 /cf/var/jail/tmp/alarmd.ts 2054B Apr 17 07:58 /cf/var/log/interactive-commands.0.gz 28.1K Apr 17 07:58 /cf/var/log/messages.0.gz 4462B Apr 17 07:41 /cf/var/tmp/cleanup-pkgs.log ...