Arch Linux

zf

Member

Registered: 2019-03-04

Posts: 11

Backup strategy: btrfs send/receive vs. backup software like borg

I am looking for a backup solution that involves: 1) mirroring external HDDs to each other (data is mostly media files), 2) backing up workstations on shutdown to NAS storage. No RAID setup and all disk except the NAS storage is offline when not used. All systems are Linux. Previously using rsync on XFS (performant filesystem), but there's no checksumming and file renames get treated as new files so data unnecessarily synced again.

Currently use Btrfs for its checksumming alone (to prevent silent errors which could propagate to backups and render them useless). Besides that, Btrfs shares what appears to be same features as those by backup software: snapshots, incremental backups, de-duplication, compression. Encryption requires Btrfs on LUKS while it's builtin with borg and similar software (I'll probably use kopia for its multithread support).

How do they compare given the similarities? I would think these features at the filesystem level might give Btrfs the edge while a backup software is filesystem-agnostic (normally a reason for others to use it to back up to third-party cloud but not applicable to my case). How does Btrfs on LUKS compare to borg in terms of performance? I assume the backups would still need to be on a checksum-supported filesystem (so btrfs on all drives?).

One advantage of borg is that you can exclude files by pattern (I'm not sure how you can get this with btrfs). Apparently deduplication works better than with Btrfs (not sure how or why).

Btrfs's snapshots are atomic, which I guess is useful if backing up a live system for consistent state.

Would backup and transfer time be comparable?

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What else should one know to make a more informed decision and what would be recommended for my case? I know there's a valid case to use both, e.g. atomic snapshots with Btrfs backed up with borg but I don't *think* I would benefit much if at all with backing software and can just rely on Btrfs until my dataset is more complex that would require patterns to exclude sets of files from being backed up.

-thc

Member

Registered: 2017-03-15

Posts: 920

Re: Backup strategy: btrfs send/receive vs. backup software like borg

Why not working "top-down" from your protection needs (instead of "bottom-up" from capabilities of products)?

What do you want to achieve strategically? You already mentioned that one of your concerns is bit-rot (media files?).
What other kinds of protection should your strategy provide?