Lets say, you have fileserver (I have openmediavault) that has diskA and diskB, where one is for storage and other for backup. Regardless of filesystem that you use, you probably use rsync for this.

Here is a wrapper script which I created, that does rsync A > B in a way, that can
a) verify all contents (by checksum dry-run comparing them),
b) verify and sync all contents (by checksum comparing them),
c) fast-sync contents (regular) and,
d) hybrid sync, where it builds a diff-list fast using delta and then goes checksum over it. More accurate, more secure, and omits checksumming everything.

It also guards against forgetting the backslash on the source dir and allows to append extra options down to rsync.
Modify it as you like. Nothing fancy, but may be interesting for few.

https://pastebin.com/6ACkfE6i

nice , but what does this have to do with gog or games?

On my windows machines I simply use freefilesync to backup everything to all my external back devices, simple, free and secure.

Freefilesync is just a good gui around rsync. No, nothing of this what you think it is. I'll give a real example, that happed right now to recently:
- during normal backup procedure, one of your usual disks starts to report new Pending Sectors.
- you purchase two new large disks and add them into the system (messy and dangerous to run 5+ disks in non-dedicated server). I use a pretty old athlon II x2 chip in asus mb with ecc ram (it supports, including scrubing) in 19" rack under tv.
- after you install them, you format them with secure filesystem (btrfs, zfs; impossible in windows machine).
- during xfer from second old usual disk to new large disk, it suddenly also starts producing Pending Sectors. So, double hardware fall.
- what is your algorithm to solve this quickly and efficiently, especially if you have only android phone? With script I can let run the dry checksum between the damaged disks to determine what is damaged through deviation, then individually restore it, because rsync runs on the server and any device has terminal emulators and web browsers.


@Troll:
I store games on the fileserver. Make me big wide eyes, so I can **** into them via tcp tunnel, ok?

Not encountered this, however I don’t just have one or two backups. I currently have 5 terramaster raid boxes with hdd’s in. The raid takes care of internal drives. These are rotated, 1 is a regular backup of drive in the machine, 1 is a monthly (roughly), 1 for 3 months, one for 6 month, and finally one longer term. I also have a separate machine with an internal set of drives as another backup/media center, and various external drives at various points over the last 20 years. Some of these are offsite.I simply use freefilesync to do the actual sync’ing part, or terracopy+checksum if I create a new backup.
It’s not perfect of course, but it’s all pretty reliable. So far I have only had one drive fail over the years (before I went down the road of all the raid boxes). Of course, always room for more backups :o)

Nice setup! Of course I am not the one to tell people how to store files, but I once had experienced automatic overwrite by a dedicated RAID card of one RAID *degraded* disk over another.In a company, who refused investing into proper backup scheme. Result - 1 month of work lost. And in another company, they simply used dedicated WD home solution instead of proper manual controlled server to store their whole info, no backups just RAID0 on XFS running on very simplistic properietary arm chip. May your data stay safe, friend!