20.8.1 Using Send/Receive to Implement Incremental Backups

The software described in this documentation is either in Extended Support or Sustaining Support. See https://www.oracle.com/us/support/library/enterprise-linux-support-policies-069172.pdf for more information.
Oracle recommends that you upgrade the software described by this documentation as soon as possible.

20.8.1 Using Send/Receive to Implement Incremental Backups

The following procedure is a suggestion for setting up an incremental backup and restore process for a subvolume.

Create a read-only snapshot of the subvolume to serve as an initial reference point for the backup:
```
# btrfs subvolume snapshot -r /vol /vol/backup_0
```
Run sync to ensure that the snapshot has been written to disk:
```
# sync
```
Create a subvolume or directory on a btrfs file system as a backup area to receive the snapshot, for example, /backupvol.
Send the snapshot to /backupvol:
```
# btrfs send /vol/backup_0 | btrfs receive /backupvol
```
This command creates the subvolume /backupvol/backup_0.
Having created the reference backup, you can then create incremental backups as required.
To create an incremental backup:
1. Create a new snapshot of the subvolume:
```
# btrfs subvolume snapshot -r /vol /vol/backup_1
```
2. Run sync to ensure that the snapshot has been written to disk:
```
# sync
```
3. Send only the differences between the reference backup and the new backup to the backup area:
```
# btrfs send -p /vol/backup_0 /vol/backup_1 | btrfs receive /backupvol
```
  This command creates the subvolume /backupvol/backup_1.