@mulbox @dalai @jwildeboer other options are:

• borg
• bacula
• amanda
• rdiff-backup
• rclone
• rsync
• duplicity, incl. it's easy-to-use frontend: #DejaDup - available on @ubuntu / #Ubuntu
• if those are small files that are frequently changed and/or they want to collab, then maybe using git is a better alternative.

Same with backup strategies, budget, storage amount and performance requirements.

• Most of these tools can target/source any mounted filesystem, some even deal with #S3-Storage. If #privacy and #DataProtection ain't a concern and the storage itself does deduplication and compression, just regularly making tar (or pax) archives and shoving them over to the #iSCSI / #NFS / #SMB / #SSH / #FTP server is also an easy option.

• If they don't want any onsite storage, ain't subject to #GDPR and don't mind #CloudAct, but rather want to solve the problem with a #CreditCard, I'd recommend #Tarsnap by @cperciva, as it's a solid product with published source available...

Personally I touched #borg and I do think that #rdiffbackup's reverse-delta approach is good if you have growing datasets, but sometimes stupid pipes and cron'd scripts will do just fine.