Tarsnap - Simple usage

Simple usage

Even the world's best backup service is useless if it's not used properly. Fortunately, there's only two steps to proper backups:

Making backups
Testing / restoring backups

Remember that thanks to deduplication, only unique data will be uploaded. It's better to create "too many" backups rather than "not enough"!

Assumptions

This page assumes that:

You installed Tarsnap to /usr/local/bin/.
You are using a configuration file that has keyfile and cachedir set.
You have a /root directory.
You would like to use Tarsnap as the root user. If necessary, become root by running:
```
su
```

If any of those assumptions are incorrect, no problem! Simply adjust the directory names (below), or add --keyfile and --cachedir, as appropriate.

Step 1: Making backups

First, create a backup script; this may be run manually, or scheduled to run automatically.

Step 1A: Backup script

Create a /root/tarsnap-backup.sh script containing:
```
#!/bin/sh

# Set up archive name
computer=$(uname -n)
now=$(date +%Y-%m-%d_%H-%M-%S)
name=${computer}-${now}

# Create an archive
/usr/local/bin/tarsnap -c \
    -f "${name}" \
    /MY/DATADIR
```
Please note:
- We recommend using the full path, as this avoids potential problems with $PATH and crontab.
  Note: the above script assumes that you installed tarsnap into /usr/local/bin, but many package managers on Linux install it to /usr/bin instead.
- Replace /MY/DATADIR as appropriate.
  You may also list multiple directories to back up. For example, you may wish to back up:
```
/etc /home /var/www
```
- The -f command defines the "archive name" in which your data is stored on the Tarsnap servers.
  Each keyfile defines a new namespace for archive names, so don't worry about using the same naming scheme as somebody else!
  - The command $(uname -n) automatically turns into your computer's $HOSTNAME.
  - Optionally, change the format of the timestamp.
    The above command produces names in the form:
```
mycomputer-2015-08-07_13-52-46
```
Make the script executable, then run it whenever you want:
```
chmod u+x /root/tarsnap-backup.sh
```
```
/root/tarsnap-backup.sh
```
tarsnap does not print any "progress" or "completion" messages unless the user requests them with the -v or --print-stats command-line arguments.
Check that you can restore these backups with Step 2: Testing / restoring backups.

Step 1B: Automatic backups (optional)

Add this to your crontab:
```
14 5 * * * /root/tarsnap-backup.sh
```
This sets up a daily backup task, but note:
- The time shown above is generated randomly each time this page loads.
- Please do not use the same time on large numbers of systems, in order to avoid creating load bursts.
Wait a day for the script to run automatically.
Check that you can restore these backups with Step 2: Testing / restoring backups.
It is not enough to check that tarsnap-backup.sh works when you run it manually! Check the automatic backups, in case there is any problem with cron.

Step 2: Testing / restoring backups

Second, check that the previous backup(s) worked.

See a list of archives:
```
tarsnap --list-archives | sort
```
Sample output:
```
mycomputer-2015-08-07_13-52-46
mycomputer-2015-08-09_19-37-20
mycomputer-2015-08-14_08-22-34
```
The raw output of --list-archives is not in alphabetical order [why?], so we sorted it.
Restore one of those archives:
```
tarsnap -x -f mycomputer-2015-08-09_19-37-20
```
Replace mycomputer-2015-08-09_19-37-20 with the appropriate archive name.
Check that the files and directories are what you expect.

More advanced usage

There are many other options available with tarsnap. We recommend reading the tips, then the general usage documentation or read the man pages.