HOWTO: Prune backups made with Relax and Recover #rear #linux

I am backing up my Linux machines bare-metal with ReaR, in the form of weekly full backups and incrementals. ReaR does a great job but doesn’t cleanup old backups by itself, so if you do nothing you’re filing up your backup server sooner or later.

As I am lazy Linux sysadmin I don’t want to cleanup leftovers manualy, so I automated it ๐Ÿ™‚ Here is how:

First: my /etc/rear/local.conf

BACKUP=NETFS
OUTPUT=ISO
CDROM_SIZE=20
BACKUP_URL=nfs://xxx.xxx.xxx.xxx/volume2/LinuxDR/rear
ISO_DIR=/mnt/ISO
ISO_PREFIX=”rear-$HOSTNAME”
BACKUP_PROG_EXCLUDE=( ‘/tmp/*’ ‘/dev/shm/*’ ‘/mnt/*’ ‘/media/*’ $VAR_DIR/output/\* )
BACKUP_SELINUX_DISABLE=1
BACKUP_TYPE=incremental
FULLBACKUPDAY=Fri
NETFS_PREFIX=”$HOSTNAME”root@lamp02:~#

This will create a full backup every friday, and incrementals on all other days.

In the picture below you see what happens if you let things run it’s course:

files_lamp02

I have got 11 backup archives of which I only need 4 (today) to recover when needed. The archives with an “F” in their name are full backups, the other ones (with “I”) are incrementals. There are also two important files here, basebackup.txt and timestamp.txt. Those two files actually do sort of the same: tell the system when the last full backup was made. ReaR needs this for restoring the system, using the correct files. I only need timestamp.txt for my cleanup job, but I could also use basebackup.txt for them. What’s in those files is not important to me, I use the time and date they where created or modified. Today is march 17, so every archive created before the last full backup (march 13 in this case) may be deleted.

To find out what files can be deleted you can issue the following command in the terminal:

find /media/nfs/lamp02/*tar.gz -type f ! -newer /media/nfs/lamp02/timestamp.txt

(make sure to adjust the path to your own situation!)

Output:

term_lamp02

To delete them issue the following command:

find /media/nfs/lamp02/*tar.gz -type f ! -newer /media/nfs/lamp02/timestamp.txt | xargs rm -f

(Again, adjust your paths!)

All files created before the last full backup will be gone, keeping your backup server clean ๐Ÿ™‚
The only thing you have to do now is create a proper cronjob to automate this. Be sure the command runs AFTER the backups are complete!

For the best results you can do this daily. If you feel you want to keep your files longer, maybe a month, you can tweak around to accomplish that. Maybe I will update this posting with my own solution for that, although in my case I do not need it.

Happy Linux’ing!

(Edit: this posting is now in the official rear user documentation, which is kinda cool)
(Edit 2: people keep asking me how to make incremental backups with ReaR, so I inserted my /etc/rear/local.conf above)

3 Responses

  1. Using timestamp.txt only works
    up to ReaR version 1.19.
    In ReaR version 2.0 incremental backups
    are implemented different, see

    https://github.com/rear/rear/issues/1152

    • Herman says:

      Hi,

      I am not able or do any work on this at the moment, maybe next week.
      The easiest quick and dirty solution might be to create the file yourself (pre backup command) e.g. touch /path/Times tap.txt) But I won’t be sure until I test it myself.

      However, as stated on github, there may be better solution by using the files itself. I’ll look into that sometime.

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