# Dump

Dump is a very useful tool for backing up entire partitions on OpenBSD. It can be done remotely.

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

## Dump Primer

[dump](/https://man.openbsd.org/dump) is a classic BSD tool for backing up entire filesystems.

Before you dump, make sure you have enough disk space for the entire dump. 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


Dumping /home will require at least 28.7G of space.

Here's a simple way to dump your /home folder:

    $ doas dump -a -f home.dmp /home


This will create home.dmp in your current directory. `-f` tells you where the dump file will be created, `/home` is the partition, and `-a` tells dump to "auto-size".

To restore from the dump file to the current directory, first check the size of the dump:

    $ du -sh home.dmp
    29G   home.dmp


We will need at least 29G of disk space in order to restore `home.dmp`.

    $ doas restore -rf home.dmp


`-r` restores the file system and `-f` reads it from the file home.dmp.

**NOTE**: It is recommended that you restore on a newly created filesystem, see [the man page](/https://man.openbsd.org/restore) for details.

## nodump flags

Some files do not need to be backed up because they can easily be downloaded elsewhere. These files can be set to `nodump` using `chflags`. You can then use `ls -lo` to view the special flag:

    $ chflags nodump /path/to/file
    $ ls -lo /path/to/file
    -rw-------  1 username  group  nodump 4452 Dec 29 18:53 file


For example, if you never edit or store any irreplaceable files in /usr, you can run:

    $ doas chflags -R nodump /usr
    $ ls -lo /usr
    drwxr-xr-x   7 root   wheel  nodump  512 Oct  4 18:47 X11R6
    drwxr-xr-x   2 root   wheel  nodump 5632 Nov 21 22:17 bin
    drwxr-xr-x   2 root   wheel  nodump 1024 Nov 21 22:14 games
    drwxr-xr-x  33 root   bin    nodump 3072 Nov 21 22:14 include
    drwxr-xr-x   7 root   wheel  nodump 4608 Dec  8 19:22 lib
    ...


To remove the nodump flag, run:

    $ chflags -R dump /path/to/file
    $ ls -lo /path/to/file
    -rw-------  1 username   group  - 4452 Dec 29 18:53 file


## Options

Let's add some helpful options:

    $ doas dump -0 -a -h 0 -f home.dmp /home


`-0` requests a full backup (a complete copy of the file system). You can use `-1`, `-2` and so forth to perform an incremental backup: only files that are new or modified since the last dump of a lower level are copied.

`-h 0` makes dump obey `nodump` flags for dumps at or above level 0 (in other words, always obey nodump flags).

`-u` adds time of last backup to `/etc/dumpdates`, and `security(8)` will notify you once it has been passed since last backup.

## Dump over SSH

You can dump to standard output instead of to a file by specifying `-f -`:

**WARNING**: Do not actually run the next line of code, or else your screen will be garbled and your system may crash. Type `ctrl+c` to cancel if you already have, and type `reset` if your screen has been garbled.

    $ doas dump -0 -a -u -h 0 -f - /home


We can redirect standard output to a file:

    $ doas dump -0 -a -u -h 0 -f - /home > home.dmp


We can use a remote host to run the dump command using ssh, then redirect the standard output to a file:

    $ ssh example.ircnow.org "doas dump -0 -a -u -h 0 -f - /home" > home.dmp


We take this idea and create a script with it in the next section.

## Complete Functions

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

    dump-ssh () {
            echo "Dumping in $PWD: type ctrl+c to abort, enter to continue"
            read $cancel
            if [ $1 ] ; then
                    remote=$1
            else
                    remote=user@example.ircnow.org
            fi
            ssh $remote "doas dump -0 -a -u -h 0 -f - /" > root.dmp
            ssh $remote "doas dump -0 -a -u -h 0 -f - /home" > home.dmp
            ssh $remote "doas dump -0 -a -u -h 0 -f - /home/vmm" > vmm.dmp
            ssh $remote "doas dump -0 -a -u -h 0 -f - /mnt" > mnt.dmp
            ssh $remote "doas dump -0 -a -u -h 0 -f - /var" > var.dmp
            ssh $remote "doas dump -0 -a -u -h 0 -f - /var/www/htdocs" > htdocs.dmp
            ssh $remote "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
    }
    dump-local () {
            echo "Dumping in $PWD: type ctrl+c to abort, enter to continue"
            read $cancel
            doas dump -0 -a -u -h 0 -f - / > root.dmp
            doas dump -0 -a -u -h 0 -f - /home > home.dmp
            doas dump -0 -a -u -h 0 -f - /home/vmm > vmm.dmp
            doas dump -0 -a -u -h 0 -f - /mnt > mnt.dmp
            doas dump -0 -a -u -h 0 -f - /var > var.dmp
            doas dump -0 -a -u -h 0 -f - /var/www/htdocs > htdocs.dmp
            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
    }


`dump-local` will make a complete local backup of the current system, and `dump-ssh` will make a complete remote backup of the server you specify.

**WARNING**: If you have any other partitions besides the ones in the function, you must add them, or the partition will **not** get backed up.

Source it, then call it on the server:

    $ . ~/.profile
    $ dump-ssh example.ircnow.org
    $ dump-local