/btrfs-snaprotate

Creation and rotation of btrfs snapshots

Primary LanguagePythonGNU General Public License v3.0GPL-3.0

btrfs_snaprotate

Description

btrfs_snaprotate is a tool for creating and rotating BTRFS snapshots. It can designed to be used to create time-based snapshots of BTRFS subvolumes and delete old ones, so only a specified number of snapshots remain. It is designed to be used in conjunction with a time based scheduling system (such as cron), but can also be used with event-based scheduling or manually.

Installation

TBD

Usage

btrfs_snaprotate is a command line tool. When invoked on a specific BTRFS subvolume, it creates a directory in that subvolume (target directory) in which it creates a single snapshot. The snapshot is named label_timestamp, where label is an ID that can be used to group logical classes of snapshots together (for example daily, hourly, before_backup) and is user selecatble. The timestamp is generated at second granularity by btrfs_snaprotate and appended to the label. The timestamp has the format: YYYY-MM-DD_hh:mm:ss (MM - Month number, mm - minute). After a new snapshot has been created,

btrfs_snaprotate is invoked with the following command line options:

   btrfs_snaprotate [-l|--label=label] [-k|--keep=num] [-a|--after=command]
                    [-t|--target=dir] [-v] subvolume

  • subvolume - The subvolume to snapshot. This is the only mandatory argument.

  • label - The label attached to the snapshot name. If not specified, defaults to the last directory component of the subvolume.

  • keep - Number of snapshots to keep. After snapshot creation, btrfs_snaprotate will try to delete the oldest snapshot, such that no more than the specified number of snapshots remain. If the number of snapshots is equal or less than the specifed keep parameter, no snapshot will be deleted. This parameter only applies to snapshots that have a label identical to the label of the snapshot that was created.

  • target - A directory, located under the subvolume, that holds the created snapshot. If not specified, the default is .snapshot.

  • after - A command to run right after the creation of the new snapshot and the (optional) deletion of the old snapshots. The string passed to this argument is run under the system' default shell. It has the following environment variables defined:

    • SNAPSUBVOL - The subvolume that was snapshot
    • SNAPTARGET - The directory in which the snapshots are stored
    • SNAPRECENT - The most recent snapshot

  • v - Increase log verbosity