zfs_autobackup/README.md

# ZFS autobackup

Introduction
============

ZFS autobackup is used to periodicly backup ZFS filesystems to other locations. This is done using the very effcient zfs send and receive commands.

It has the following features:
* Automaticly selects filesystems to backup by looking at a simple ZFS property. (recursive)
* Creates consistent snapshots. (takes all snapshots at once, atomic.)
* Multiple backups modes:
  * "push" local data to a backup-server via SSH.
  * "pull" remote data from a server via SSH and backup it locally.
  * Backup local data on the same server.
* Can be scheduled via a simple cronjob or run directly from commandline.
* Supports resuming of interrupted transfers. (via the zfs extensible_dataset feature)
* Backups and snapshots can be named to prevent conflicts. (multiple backups from and to the same filesystems are no problem)
* Always creates a new snapshot before starting.
* Checks everything and aborts on errors.
* Ability to 'finish' aborted backups to see what goes wrong.
* Easy to debug and has a test-mode. Actual unix commands are printed.
* Keeps latest X snapshots remote and locally. (default 30, configurable)
* Easy installation:
  * Only one host needs the zfs_autobackup script. The other host just needs ssh and the zfs command.
  * Written in python and uses zfs-commands, no 3rd party dependencys or libraries.
  * No seperate config files or properties. Just one command you can copy/paste in your backup script.

Usage
====
```
usage: zfs_autobackup [-h] [--ssh-source SSH_SOURCE] [--ssh-target SSH_TARGET]
                      [--keep-source KEEP_SOURCE] [--keep-target KEEP_TARGET]
                      [--no-snapshot] [--no-send] [--resume]
                      [--strip-path STRIP_PATH] [--destroy-stale]
                      [--clear-refreservation] [--clear-mountpoint]
                      [--filter-properties FILTER_PROPERTIES] [--rollback]
                      [--test] [--verbose] [--debug]
                      backup_name target_fs

ZFS autobackup v2.2

positional arguments:
  backup_name           Name of the backup (you should set the zfs property
                        "autobackup:backup-name" to true on filesystems you
                        want to backup
  target_fs             Target filesystem

optional arguments:
  -h, --help            show this help message and exit
  --ssh-source SSH_SOURCE
                        Source host to get backup from. (user@hostname)
                        Default local.
  --ssh-target SSH_TARGET
                        Target host to push backup to. (user@hostname) Default
                        local.
  --keep-source KEEP_SOURCE
                        Number of days to keep old snapshots on source.
                        Default 30.
  --keep-target KEEP_TARGET
                        Number of days to keep old snapshots on target.
                        Default 30.
  --no-snapshot         dont create new snapshot (usefull for finishing
                        uncompleted backups, or cleanups)
  --no-send             dont send snapshots (usefull to only do a cleanup)
  --resume              support resuming of interrupted transfers by using the
                        zfs extensible_dataset feature (both zpools should
                        have it enabled) Disadvantage is that you need to use
                        zfs recv -A if another snapshot is created on the
                        target during a receive. Otherwise it will keep
                        failing.
  --strip-path STRIP_PATH
                        number of directory to strip from path (use 1 when
                        cloning zones between 2 SmartOS machines)
  --destroy-stale       Destroy stale backups that have no more snapshots. Be
                        sure to verify the output before using this!
  --clear-refreservation
                        Set refreservation property to none for new
                        filesystems. Usefull when backupping SmartOS volumes.
                        (recommended)
  --clear-mountpoint    Sets canmount=noauto property, to prevent the received
                        filesystem from mounting over existing filesystems.
                        (recommended)
  --filter-properties FILTER_PROPERTIES
                        Filter properties when receiving filesystems. Can be
                        specified multiple times. (Example: If you send data
                        from Linux to FreeNAS, you should filter xattr)
  --rollback            Rollback changes on the target before starting a
                        backup. (normally you can prevent changes by setting
                        the readonly property on the target_fs to on)
  --test                dont change anything, just show what would be done
                        (still does all read-only operations)
  --verbose             verbose output
  --debug               debug output (shows commands that are executed)
```

Backup example
==============

In this example we're going to backup a SmartOS machine called `smartos01` to our fileserver called `fs1`.

Its important to choose a unique and consistent backup name. In this case we name our backup: `smartos01_fs1`.

Select filesystems to backup
----------------------------

On the source zfs system set the ```autobackup:smartos01_fs1``` zfs property to true:
```
[root@smartos01 ~]# zfs set autobackup:smartos01_fs1=true zones
[root@smartos01 ~]# zfs get -t filesystem autobackup:smartos01_fs1
NAME                                                PROPERTY                  VALUE                     SOURCE
zones                                               autobackup:smartos01_fs1  true                      local
zones/1eb33958-72c1-11e4-af42-ff0790f603dd          autobackup:smartos01_fs1  true                      inherited from zones
zones/3c71a6cd-6857-407c-880c-09225ce4208e          autobackup:smartos01_fs1  true                      inherited from zones
zones/3c905e49-81c0-4a5a-91c3-fc7996f97d47          autobackup:smartos01_fs1  true                      inherited from zones
...
```

Because we dont want to backup everything, we can exclude certain filesystem by setting the property to false:
```
[root@smartos01 ~]# zfs set autobackup:smartos01_fs1=false zones/backup
[root@smartos01 ~]# zfs get -t filesystem autobackup:smartos01_fs1
NAME                                                PROPERTY                  VALUE                     SOURCE
zones                                               autobackup:smartos01_fs1  true                      local
zones/1eb33958-72c1-11e4-af42-ff0790f603dd          autobackup:smartos01_fs1  true                      inherited from zones
...
zones/backup                                        autobackup:smartos01_fs1  false                     local
zones/backup/fs1                                    autobackup:smartos01_fs1  false                     inherited from zones/backup
...
```


Running zfs_autobackup
----------------------
There are 2 ways to run the backup, but the endresult is always the same. Its just a matter of security (trust relations between the servers) and preference.

First install the ssh-key on the server that you specify with --ssh-source or --ssh-target.

Method 1: Run the script on the backup server and pull the data from the server specfied by --ssh-source. This is usually the preferred way and prevents a hacked server from accesing the backup-data:
```
root@fs1:/home/psy# ./zfs_autobackup --ssh-source root@1.2.3.4 smartos01_fs1 fs1/zones/backup/zfsbackups/smartos01.server.com --verbose 
Getting selected source filesystems for backup smartos01_fs1 on root@1.2.3.4
Selected: zones (direct selection)
Selected: zones/1eb33958-72c1-11e4-af42-ff0790f603dd (inherited selection)
Selected: zones/325dbc5e-2b90-11e3-8a3e-bfdcb1582a8d (inherited selection)
...
Ignoring: zones/backup (disabled)
Ignoring: zones/backup/fs1 (disabled)
...
Creating source snapshot smartos01_fs1-20151030203738 on root@1.2.3.4
Getting source snapshot-list from root@1.2.3.4
Getting target snapshot-list from local
Tranferring zones incremental backup between snapshots smartos01_fs1-20151030175345...smartos01_fs1-20151030203738
...
received 1.09MB stream in 1 seconds (1.09MB/sec)
Destroying old snapshots on source
Destroying old snapshots on target
All done
```

Method 2: Run the script on the server and push the data to the backup server specified by --ssh-target:
```
./zfs_autobackup --ssh-target root@2.2.2.2 smartos01_fs1 fs1/zones/backup/zfsbackups/smartos01.server.com --verbose  --compress
...
All done

```

Tips
====

 * Set the ```readonly``` property of the target filesystem to ```on```. This prevents changes on the target side. If there are changes the next backup will fail and will require a zfs rollback. (by using the --rollback option for example)
 * Use ```--clear-refreservation``` to save space on your backup server.
 * Use ```--clear-mountpoint``` to prevent the target server from mounting the backupped filesystem in the wrong place during a reboot. If this happens on systems like SmartOS or Openindia, svc://filesystem/local wont be able to mount some stuff and you need to resolve these issues on the console.

Speeding up SSH and prevent connection flooding
-----------------------------------------------

Add this to your ~/.ssh/config:
```
Host *
    ControlPath ~/.ssh/control-master-%r@%h:%p
    ControlMaster auto
    ControlPersist 3600
```

This will make all your ssh connections persistent and greatly speed up zfs_autobackup for jobs with short intervals.

Thanks @mariusvw :)


Specifying ssh port or options
------------------------------

The correct way to do this is by creating ~/.ssh/config:
```
Host smartos04
    Hostname 1.2.3.4
    Port 1234
    user root
    Compression yes 
```

This way you can just specify smartos04

Also uses compression on slow links.

Look in man ssh_config for many more options.

Troubleshooting
===============

`cannot receive incremental stream: invalid backup stream`

This usually means you've created a new snapshot on the target side during a backup.
 * Solution 1: Restart zfs_autobackup and make sure you dont use --resume. If you did use --resume, be sure to "abort" the recveive on the target side with zfs recv -A.
 * Solution 2: Destroy the newly created snapshot and restart zfs_autobackup.


`internal error: Invalid argument`

In some cases (Linux -> FreeBSD) this means certain properties are not fully supported on the target system.

Try using something like: --filter-properties xattr


Restore example
===============

Restoring can be done with simple zfs commands. For example, use this to restore a specific SmartOS disk image to a temporary restore location:


```
root@fs1:/home/psy#  zfs send fs1/zones/backup/zfsbackups/smartos01.server.com/zones/a3abd6c8-24c6-4125-9e35-192e2eca5908-disk0@smartos01_fs1-20160110000003 | ssh root@2.2.2.2 "zfs recv zones/restore"
```

After that you can rename the disk image from the temporary location to the location of a new SmartOS machine you've created.

Snapshotting example
====================

Sending huge snapshots cant be resumed when a connection is interrupted: Next time zfs_autobackup is started, the whole snapshot will be transferred again. For this reason you might want to have multiple small snapshots.

The --no-send option can be usefull for this. This way you can already create small snapshots every few hours:
````
[root@smartos2 ~]# zfs_autobackup --ssh-source root@smartos1 smartos1_freenas1 zones --verbose --ssh-cipher chacha20-poly1305@openssh.com --no-send
````

Later when our freenas1 server is ready we can use the same command without the --no-send at freenas1. At that point the server will receive all the small snapshots up to that point.



Monitoring with Zabbix-jobs
===========================

You can monitor backups by using my zabbix-jobs script. (https://github.com/psy0rz/stuff/tree/master/zabbix-jobs)

Put this command directly after the zfs_backup command in your cronjob:
```
zabbix-job-status backup_smartos01_fs1 daily $?
```

This will update the zabbix server with the exitcode and will also alert you if the job didnt run for more than 2 days.