Bash scripts for efficiently and (relatively) safely backing up a linux system using LVM snapshots and rsync.
See the no-lvm branch for a simpler version which does without LVM.
This produces a set of folders, each of which (apparently) contain a full copy of the backed-up filesystem at particualar times in the past. In reality, the files are hardlinked, so they only take up the space of the oldest backup plus any changes made since.
The scripts aren't perfect, and may need some tweaking to work with your system.
You need LVM set up, with enough unallocated space in volume groups to create logical volumes for the backup and the temporary snapshop buffer. The backup size must be large enough to contain all the data in the logical volume to be backed up and any changes that may occur over the period that the backups are kept for. The buffer size just needs to be large enough to contain any changes to the logical volume that is being backed up while the backup is progressing.
The main script is backup-daily:
backup-daily BACKUP_VOLUME BACKUP_MOUNT BACKUP_SIZE BUFFER_SIZE
For example, say you have a filesystem on the logical volume device
/dev/mapper/vg_system-lv_home and you wish to create a backup
mounted at /mnt/backup with 64Gb of backup space and 592Mb of buffer
space, the command is:
backup-daily /dev/mapper/vg_system-lv_home /mnt/backup 64G 592M
The other scripts, backup-weekly and backup-monthly, simply delete
the oldest backups and rename intermediate backups.
For automated use, put the scripts somewhere convenient,
e.g. /etc/backups/, and set up a cron job to run them with
appropriate frequency (see the *.cron examples).