RE: Roon ROCK and backup.
I run ROCK on a NUC8-i5. 256gb SSD for OS and database. 2tb nvme drive for internal storage. The internal storage folder is mapped to my Windows Server 2019 as a network drive. I use RealTimeSync for windows on the server to sync this folder to another windows drive that actually resides in my Synology NAS (RAID6) via an iSCSI LUN. The synced windows folder with all my media then backs up to CrashPlan automatically.
So whenever I copy music to the internal ROCK drive, it automatically backs up to my RAID6 NAS and to CrashPlan. The ROCK database automatically backs itself up to a different folder on the synology. No issues so far over the last several months.
Does CrashPlan have command line interfaces or do you have to use a UI? My server runs a Proxmox ZFS array where the main share is OpenMediaVault and I plan to use Sanoid/Syncoid to backup to a headless Ubuntu server computer, but still need a backup for that.