svn-backup2

The svn-backup2 application is a frugal Subversion backup solution inspired by adamonduty/svn-backup. Orignally written and tested for Debian 12 in Bash but could be adapted to other systems.

At first run it generates a full-backup and runs svnadmin verify.

This script is designed to be run as root. But it is possible when correct permissions are given to run as non-root user.

Features and limitations

Single file mode

It creates and updates a single file per repository and consists of multiple gzip compressed archives. It is sha256 checksumed to detect bit-rot before appending a new incremental backup. This is possible because svnadmin load is able to load from a stream of multiple dumps. This is not rsync efficient.

• Set SVNBACKUP2_CFG_USE_SINGLE_FILE=1 (and SVNBACKUP2_CFG_BACKUP_NR_DATASETS=0)
• Only supports one subversion root path which can contain multiple repositories
• Single repository backup file for simplicity of restoration
• Can only restore the whole backup file into an empty repository
• ${SVNBACKUP2_CFG_BACKUP_PATH}/<repository name>.svnbackup2: Backup file (multiple concatinated gzip files) (configurable)

Dataset mode

In dataset mode a full backup is written and per incremental run a new file is created. This is rsync efficient.

• Set SVNBACKUP2_CFG_BACKUP_NR_DATASETS=1 or higher (and SVNBACKUP2_CFG_USE_SINGLE_FILE=0)
• ${SVNBACKUP2_CFG_BACKUP_PATH}/<repository name>/dataset_<n>/<repository name>_full.svnbackup2: Full backup in dataset n
• ${SVNBACKUP2_CFG_BACKUP_PATH}/<repository name>/dataset_<n>/<repository name>_incr_rev<x>-rev<y>.svnbackup2: Incremental backup in dataset n

Installation

Install dependencies on Debian Linux 12:

apt install subversion curl

Download and install version 0.2.2 to /usr/local/bin/svn-backup2 in a oneliner with curl:

FILE=/usr/local/bin/svn-backup2 &&
curl -o ${FILE} https://raw.githubusercontent.com/xor-gate/svn-backup2/v0.2.2/svn-backup2 &&
chmod -v 755 ${FILE} &&
chown -v root:root ${FILE}

Paths

• /etc/svn-backup2.conf: Configuration file
• /var/log/svn-backup2.log: Logfile
• /srv/svn: Subversion repositories root path (configurable)
• /var/tmp/svn-backup2/<repository name>.state: State of a single repository backup

Configuration file (/etc/svn-backup2.conf)

The file is a set of shell environment variables. It will be created on first run with the following defaults:

SVNBACKUP2_CFG_VERSION=1
SVNBACKUP2_CFG_REPOSITORIES_PATH="/srv/svn"
SVNBACKUP2_CFG_BACKUP_PATH="/srv/svn-backup2"
SVNBACKUP2_CFG_USE_SINGLE_FILE=1
SVNBACKUP2_CFG_BACKUP_NR_DATASETS=0

Repository backup state file

A single repository backup state file is a dump of SVNBACKUP2_REPO_STATE_* environment variables

Example:

SVNBACKUP2_REPO_STATE_CHECKSUM=a911966efe3b069c970ae5511e4a3e6c169bf993e9a3443d841d5d9002447388
SVNBACKUP2_REPO_STATE_LAST_BACKUP_DURATION=1
SVNBACKUP2_REPO_STATE_LAST_BACKUP_END_TIME=1706279396
SVNBACKUP2_REPO_STATE_LAST_BACKUP_START_TIME=1706279396
SVNBACKUP2_REPO_STATE_YOUNGEST=0

Usage

Usage: svn-backup2 [operation] <args>
  none                            All repositories are checked and backuped
  version                         Print the version
  full [<repository name> | all]  Force full backup on given repository or "all"

Cron in dataset mode

We use cron to cycle between the different datasets. As an example we generate a full backup once a month. And the other days an incremental:

5 2 1 * * /usr/local/bin/svn-backup2 full all
5 2 2-31 * * /usr/local/bin/svn-backup2

Restoration of single file

svn-backup2 generates simple subversion dumpfiles that can be stream loaded into svnadmin load.

Step 1: Create an empty repository

svnadmin create /srv/svn/repository_1

Step 2: Uncompress the dumpfile as stream and load into svnadmin

zcat /srv/svn-backup2/repository_1.svnbackup2 | svnadmin load /srv/svn/repository_1

Step 3: There is no step 3!

A simple shell command can load all repositories at once:

find . -type f -name "*.svnbackup2" | while read i; do repository_name=`basename "$i" .svnbackup2`; svnadmin create "$repository_name" && zcat "$i" | svnadmin load "$repository_name"; done

Restoration of dataset

With ls you can sort on creation date and load it with svnadmin

$ svnadmin create /tmp/testrepo
$ for backup in `ls -1 -r -t --time=creation /srv/svn-backup2/testrepo2/dataset_1/*`; do zcat $backup | svnadmin load /tmp/testrepo; done

License

svn-backup2 is copyright 2024 by Jerry Jacobs and distributed under the terms of the MIT License. See the LICENSE file for further information.

Alternatives

• adamonduty/svn-backup written in Ruby (defunc on Debian 12)
• loresoft/SvnTools written in C#
• ghstwhl/SVNBackup written in Perl
• gcraig/SVNBackup written in Python
• subversion-tools multiple tools written in C/Perl
• avalax/svnbackup shell script using svn-hot-backup