Yes, I ran "request system storage cleanup".
Unfortunetly, attempting to install jweb from a usb stick did not work. There simply isn't enough space on the /dev/da0s1a filesystem for the jweb package. Below is the output from the attempted install.
root@juniper> request system software add /var/tmp/usb/jweb-15.1R4.6-signed.tgz Checking pending install on fpc0 Validating on fpc0 Available space: 16104 require: 52844 WARNING: The root filesystem is low on free disk space. WARNING: This package requires 52844k free, but there WARNING: is only 16104k available. WARNING: This installation attempt will be aborted. WARNING: If you wish to force the installation despite these warnings WARNING: you may use the 'force' option on the command line. ERROR: jweb-15.1R4.6-signed fails requirements check
Is there a way to give the root partition more space, or to get the jweb package installed onto another partition that has enough free space?