Just Backup Btrfs Save

Just backup btrfs

Script that does just that - creates backups using snapshot of btrfs filesystem. Also it makes rotation of snapshots by removing old ones and keeping as many snapshots as you want.

Why?

I wanted simple thing: store snapshots of several subvolumes in one place and keep specific number of snapshots for each time interval (more recent and less elder snapshots).

I was wondered that no existing solutions fit my needs, so I decided to write it:)

Requirements

• php-cli (version 5.4+)
• php-sqlite3

You can get them both on Ubuntu 15.10-:

sudo apt-get install php5-cli php5-sqlite

Ubuntu 16.04+:

sudo apt-get install php-cli php-sqlite3

Also enable sqlite3 extension since it may be disabled by default. Ubuntu 15.10-:

sudo php5enmod sqlite3

Ubuntu 16.04+

sudo phpenmod sqlite3

Installation

The whole thing is a single file, so first way is just to copy file just-backup-btrfs somewhere.

Alternatively you can install it globally using Composer like this:

sudo COMPOSER_BIN_DIR=/usr/local/bin composer global require nazar-pc/just-backup-btrfs

COMPOSER_BIN_DIR=/usr/local/bin will instruct Composer to install binary to /usr/local/bin so that you'll be able to call just-backup-btrfs right after installation. Alternatively you can skip it and add ~/.composer/vendor/bin/ to your PATH.

Removal

If installed manually - just remove file, if installed with Composer - remove it with:

sudo COMPOSER_BIN_DIR=/usr/local/bin composer global remove nazar-pc/just-backup-btrfs

Or without COMPOSER_BIN_DIR=/usr/local/bin if you didn't use it during installation.

Usage

Script expects configuration file to be present at location /etc/just-backup-btrfs.json, example of such file you can find below. Also, if you want to use other path to config file - specify it as argument.

There are few ways to run script.

sudo php just-backup-btrfs

or mark file as executable and just

sudo ./just-backup-btrfs

or mark as executable and put into /etc/cron.daily to make backups every day.

With custom path to config file:

sudo ./just-backup-btrfs /path/to/config.json

Output will be like this:

Just backup btrfs started...
CMD: /bin/btrfs subvolume snapshot -r "/" "/backup/root/2016-03-12_16:29:52"
CMD: sync
Snapshot 2016-03-12_16:29:52 for / created successfully
CMD: mount
Mounting root subvolume skipped, since already mounted
Making incremental backup
CMD: /bin/btrfs send -p "/backup/root/2016-03-12_16:26:48" "/backup/root/2016-03-12_16:29:52" | /bin/btrfs receive /tmp/just_backup_btrfs_45e177f34dddc33a5b1537ce8f4913ba/root
At subvol /backup/root/2016-03-12_16:29:52
CMD: /bin/btrfs subvolume delete "/backup_hdd/root/2016-03-11_16:30:01"
Old snapshot 2016-03-11_16:30:01 removed successfully from /backup_hdd/root
Creating incremental backup 2016-03-12_16:29:52 of / to /backup_hdd/root finished successfully
Unmounting root subvolume skipped
CMD: /bin/btrfs subvolume delete "/backup/root/2016-03-12_15:30:01"
Old snapshot 2016-03-12_15:30:01 removed successfully from /backup/root
CMD: /bin/btrfs subvolume snapshot -r "/home" "/backup/home/2016-03-12_16:30:04"
CMD: sync
Snapshot 2016-03-12_16:30:04 for /home created successfully
CMD: mount
Mounting root subvolume skipped, since already mounted
Making incremental backup
CMD: /bin/btrfs send -p "/backup/home/2016-03-12_16:26:51" "/backup/home/2016-03-12_16:30:04" | /bin/btrfs receive /tmp/just_backup_btrfs_45e177f34dddc33a5b1537ce8f4913ba/home
At subvol /backup/home/2016-03-12_16:30:04
CMD: /bin/btrfs subvolume delete "/backup_hdd/home/2016-03-11_16:30:08"
Old snapshot 2016-03-11_16:30:08 removed successfully from /backup_hdd/home
Creating incremental backup 2016-03-12_16:30:04 of /home to /backup_hdd/home finished successfully
Unmounting root subvolume skipped
CMD: /bin/btrfs subvolume delete "/backup/home/2016-03-12_15:30:05"
Old snapshot 2016-03-12_15:30:05 removed successfully from /backup/home
CMD: /bin/btrfs subvolume snapshot -r "/web" "/backup/web/2016-03-12_16:30:30"
CMD: sync
Snapshot 2016-03-12_16:30:30 for /web created successfully
CMD: mount
Mounting root subvolume skipped, since already mounted
Making incremental backup
CMD: /bin/btrfs send -p "/backup/web/2016-03-12_16:26:58" "/backup/web/2016-03-12_16:30:30" | /bin/btrfs receive /tmp/just_backup_btrfs_45e177f34dddc33a5b1537ce8f4913ba/web
At subvol /backup/web/2016-03-12_16:30:30
CMD: /bin/btrfs subvolume delete "/backup_hdd/web/2016-03-11_16:30:26"
Old snapshot 2016-03-11_16:30:26 removed successfully from /backup_hdd/web
Creating incremental backup 2016-03-12_16:30:30 of /web to /backup_hdd/web finished successfully
Unmounting root subvolume skipped
CMD: /bin/btrfs subvolume delete "/backup/web/2016-03-12_15:30:15"
Old snapshot 2016-03-12_15:30:15 removed successfully from /backup/web
Just backup btrfs finished!

Also you can call it with cron or in some other way:)

What it actually does?

• reads configuration from /etc/just-backup-btrfs.json
• creates destination_within_partition/history.db SQLite database if it doesn't exists yet
• creates snapshot with date as the name inside destination_within_partition
• creates backups (copies of snapshots inside destination_within_partition) inside destination_other_partition for the case when source filesystem crashes
• store snapshot name, date and how long snapshot should be kept in destination_within_partition/history.db (and destination_other_partition/history.db, since backups might have own retention settings)
• reads old snapshots stored in destination_within_partition/history.db (and destination_other_partition/history.db) and remove them from history.db and from filesystem

Configuration

Configuration options are especially made self-explanatory:

[
	{
		"source_mounted_volume"        : "/",
		"destination_within_partition" : "/backup/root",
		"destination_other_partition"  : null,
		"date_format"                  : "Y-m-d_H:i:s",
		"keep_snapshots"               : {
			"hour"  : 60,
			"day"   : 24,
			"month" : 30,
			"year"  : 48
		}
	},
	{
		"source_mounted_volume"        : "/home",
		"destination_within_partition" : "/backup/home",
		"destination_other_partition"  : "/backup_external/home",
		"date_format"                  : "Y-m-d_H:i:s",
		"optimize_mounts"              : false,
		"keep_snapshots"               : {
			"hour"  : 120,
			"day"   : 48,
			"month" : 60,
			"year"  : 96
		},
		"keep_other_snapshots"         : {
			"hour"  : -1,
			"day"   : 96,
			"month" : 120,
			"year"  : 192
		},
		"minimum_delete_count"         : 10,
		"minimum_delete_count_other"   : 10
	}
]

• source_mounted_volume - string, absolute path, subvolume to backup/create snapshot of
• destination_within_partition - string, absolute path, where to store snapshots, should be the same partition as source_mounted_volume
• destination_other_partition - string, absolute path (or null if not needed), where to store actual backup, expected to be another BTRFS partition
• date_format - string, date format as for PHP date() function
• keep_snapshots - array with keys hour, day, month and year, each key contains number of snapshots that must be kept within corresponding time interval (-1 means unlimited)
• keep_other_snapshots - the same as keep_snapshots, but for backups, keep_snapshots by default
• optimize_mounts - allows to avoid constant remounting root during external backups since it might be slow; true by default, might be disabled if necessary
• minimum_delete_count - minimum number of snapshots to remove, is used to decrease fragmentation and thus improve performance, 1 by default
• minimum_delete_count_other - the same as minimum_delete_count, but for backups, minimum_delete_count by default

Save this config as /etc/just-backup-btrfs.json and customize as you like.

License

MIT, feel free to hack it and share!