sanoid/README.md

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<img src="http://openoid.net/gplv3-127x51.png" width=127 height=51 align="right">Sanoid is a policy-driven snapshot management tool for ZFS filesystems.  When combined with the Linux KVM hypervisor, you can use it to make your systems <a href="http://openoid.net/transcend" target="_blank">functionally immortal</a>.  (Want an example? Watch a short real time demo of <a href="https://youtu.be/ZgowLNBsu00" target="_blank">rolling back a full-scale cryptomalware infection in seconds</a>!)

More prosaically, you can use Sanoid to create, automatically thin, and monitor snapshots and pool health from a single eminently human-readable TOML config file at /etc/sanoid/sanoid.conf.  (Sanoid also requires a "defaults" file located at /etc/sanoid/sanoid.defaults.conf, which is not user-editable.)  A typical Sanoid system would have a single cron job:

```
* * * * * /usr/local/bin/sanoid --cron
```

And its /etc/sanoid/sanoid.conf might look something like this:

```
[data/home]
	use_template = production
[data/images]
	use_template = production
	recursive = yes
	process_children_only = yes
[data/images/win7]
	hourly = 4

#############################
# templates below this line #
#############################

[template_production]
        hourly = 36
        daily = 30
        monthly = 3
        yearly = 0
        autosnap = yes
        autoprune = yes
```

Which would be enough to tell sanoid to take and keep 36 hourly snapshots, 30 dailies, 3 monthlies, and no yearlies for all datasets under data/images (but not data/images itself, since process_children_only is set).  Except in the case of data/images/win7-spice, which follows the same template (since it's a child of data/images) but only keeps 4 hourlies for whatever reason.

Sanoid also includes a replication tool, syncoid, which facilitates the asynchronous incremental replication of ZFS filesystems.  A typical syncoid command might look like this:

```
syncoid data/images/vm backup/images/vm
```

Which would replicate the specified ZFS filesystem (aka dataset) from the data pool to the backup pool on the local system, or

```
syncoid data/images/vm root@remotehost:backup/images/vm
```

Which would push-replicate the specified ZFS filesystem from the local host to remotehost over an SSH tunnel, or

```
syncoid root@remotehost:data/images/vm backup/images/vm
```

Which would pull-replicate the filesystem from the remote host to the local system over an SSH tunnel.

Syncoid supports recursive replication (replication of a dataset and all its child datasets) and uses mbuffer buffering, lzop compression, and pv progress bars if the utilities are available on the systems used.