# Rsync

[Rsync](/https://rsync.samba.org/) is a very useful tool for backing up files. It can be used remotely.

**WARNING**: If your filesystem is being actively written to, data corruption may occur.

## Rsync Primer

OpenBSD includes its own rewrite of rsync called [openrsync](/https://man.openbsd.org/openrsync). It seems to be a bit buggy so I am going to use rsync instead. The commands below, however, will work with either openrsync or rsync.

Here's how to back up the file /path/to/file on ircnow.org with username to the current directory:

    $ rsync -a username@ircnow.org:/path/to/file ./


We add the option `-a` for archive mode.

If you have multiple files, you can use the shorthand of :/path/to/second/file:

    $ rsync -a username@ircnow.org:/path/to/file :/path/to/second/file ./


This copies both /path/to/file and /path/to/second/file from ircnow.org to your current local directory.

    $ rsync -a username@ircnow.org:/path/to/file :/path/to/second/file ./


We add `-v` options to turn on verbosity (it will display each file copied).

    $ rsync -v username@ircnow.org:/path/to/file ./




## Quick Check

Before you backup your files, make sure you have enough disk space. To see how much space it will take, and how much you have available, run:

    $ df -h
    Filesystem     Size    Used   Avail Capacity  Mounted on
    /dev/sd0a     1005M    111M    844M    12%25    /
    /dev/sd0k      192G   28.7G    153G    16%25    /home
    /dev/sd0d      3.9G   22.1M    3.7G     1%25    /tmp
    /dev/sd0f     12.3G    7.3G    4.4G    63%25    /usr
    /dev/sd0e     14.7G   41.2M   14.0G     0%25    /var


Backing up /home will require at least 28.7G of space.



    $ rsync --rsync-path="doas rsync" -avz username@example.com:/home/username /dest/path/


This will copy everything in /home/username on example.com into /dest/path/. `-a` specifies this is an archive, `-v` tells rsync to be more verbose (show files), and `z` tells rsync to compress during the transfer..

(:if false:)

## Complete Functions

Put the following functions at the end of ~/.profile:

    rsync-all () {
            echo "Backing up in $PWD: type ctrl+c to abort, enter to continue"
            read $cancel
            ssh $1 "doas dump -0 -a -u -h 0 -f - /" > root.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /home" > home.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /home/vmm" > vmm.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /mnt" > mnt.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /var" > var.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /var/www/htdocs" > htdocs.dmp
            ssh $1 "doas dump -0 -a -u -h 0 -f - /usr" > usr.dmp
            date > date
            md5 root.dmp home.dmp vmm.dmp mnt.dmp var.dmp htdocs.dmp usr.dmp date > md5sum
    }
    `rsync-all` will make a complete backup of the remote system you specify.
    Source it, then call it on the server:
    $ . .profile
    $ rsync-all example.ircnow.org


(:ifend:)