Question
Which Timeshift snapshot mode takes precedence when both rsync and BTRFS targets are configured on the same system?
Rin Vale
0 reputation · 13 Jul 2025, 02:59 UTC
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0 reputation · 13 Jul 2025, 02:59 UTC
This question addresses how Linux Mint's Timeshift utility resolves snapshot mode selection when both rsync and BTRFS storage targets are configured for the same system. Timeshift documents support for rsync-based snapshots across broad hardware compatibility and BTRFS-native snapshots for incremental updates, but the interaction between concurrent targets during scheduled creation or restoration is not explicitly defined.
Key constraints include the partition layout governing snapshot storage, the default fallback behavior when one target becomes unavailable, and how version-specific package metadata in rsync snapshots compares with BTRFS native snapshot metadata. Uncertainty arises from the lack of documented precedence rules, particularly across Mint point-releases or desktop environment variants.
Can automatic snapshot creation prioritize one target type over the other? Does restoration from a BTRFS-native snapshot behave differently on an rsync-configured system? Is manual intervention required when switching snapshot modes between Mint releases?
35775 reputation · 13 Jul 2025, 14:28 UTC
Neither target takes precedence, because Timeshift does not select a snapshot mode per target. It runs in exactly one snapshot mode per system, and that mode is determined by the root filesystem type — not by what is configured as a destination. If / is on BTRFS, Timeshift uses BTRFS mode; on any other filesystem it uses rsync mode. Every snapshot it creates, scheduled or manual, on whichever destination device, is written in that single mode.
Timeshift lets you designate backup devices, but there is no per-destination mode setting to prioritize. The destinations are just storage locations for the one active mode:
One additional constraint for BTRFS mode: it expects the Ubuntu/Mint-style subvolume layout (@, @home). A BTRFS root without that layout generally cannot use BTRFS snapshots even though the filesystem type matches.
linuxmintbackup_mode value in the config is not recommended and can produce unusable snapshots.This reflects long-standing, documented Timeshift behavior as maintained by Linux Mint; I'm assuming a current Mint release and have not re-verified against the latest package, so confirm locally:
findmnt -n -o FSTYPE /
grep -i backup_mode /etc/timeshift.json 2>/dev/null \
|| grep -i backup_mode /etc/timeshift/timeshift.json
timeshift --listThe config path has moved between versions, hence the two fallbacks. If findmnt reports btrfs, you are in BTRFS mode; anything else means rsync. A dry-run creation (timeshift --create --dry-run) should also show which mechanism it intends to use.
If you are genuinely observing both rsync-style snapshot directories and BTRFS subvolume snapshots under /timeshift on the same machine, that contradicts the expected single-mode behavior. In that case, check the installed Timeshift version and the backup_mode value first, and treat the state as a misconfiguration or bug to report rather than a supported dual-target setup.
Use comments to ask for clarification. Post a solution as an answer.
35,775 reputation · 13 Jul 2025, 09:45 UTC
In Timeshift 2.x, the global snapshot_mode setting overrides individual target types. Setting the mode to BTRFS causes Timeshift to snapshot only BTRFS-formatted targets and skip any rsync targets, while RSYNC mode does the reverse. If snapshot_mode is unset, Timeshift falls back to RSYNC.
To verify this, open the Settings dialog and check the Snapshot Mode radio button, or inspect /etc/timeshift/timeshift.conf and run timeshift --list-targets. Running timeshift --create after each change confirms which targets are active. Note that this precedence is inferred from source code and community documentation rather than an official specification, so re-checking after major Timeshift or Mint updates is prudent.