When using JetBackup to backup General System files, there is a possibility that JetBackup will run infinitely as there are some directories that are always changing.
For example, the /proc directory has many directories/files that are continually being generated and deleted. System directories like these can cause issues with backups and/or lead to "infinite" loops when backing up certain directories resulting in a higher disk usage than what actually exists. For another example, including /usr would also include the JetBackup Workspace files/directories that are also constantly being created/removed.
We do have a generic list of system and server config files we recommend including in your system backups that can be found here: https://docs.jetbackup.com/manual/whm/Troubleshooting/backupSystemFiles.html
Please note that this list is generic and is based on a cPanel Server, so not all files/folders will be relevant. Additionally, I recommend working with your system administrator to look for other System files/folders that can be excluded from backups for specifically Ubuntu servers. I was able to find the following community resource that recommends excluding /proc and /sys since they are virtual filesystems: https://serverfault.com/questions/74696/linux-what-directories-should-i-exclude-when-backing-up-a-server
