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<article role="main" id="furo-main-content">
<section id="btrfs-btrfs">
<span id="storage-btrfs"></span><h1>Btrfs - <code class="docutils literal notranslate"><span class="pre">btrfs</span></code><a class="headerlink" href="#btrfs-btrfs" title="Link to this heading">¶</a></h1>
<p class="youtube_link">
<a href="https://www.youtube.com/watch?v=2r5FYuusxNc" target="_blank">
<span title="Btrfs storage and LXD" class="play_icon">▶</span>
<span title="Btrfs storage and LXD">Watch on YouTube</span>
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</p>
<p><abbr title="B-tree file system">Btrfs</abbr> is a local file system based on the <abbr title="copy-on-write">COW</abbr> principle.
COW means that data is stored to a different block after it has been modified instead of overwriting the existing data, reducing the risk of data corruption.
Unlike other file systems, Btrfs is extent-based, which means that it stores data in contiguous areas of memory.</p>
<p>In addition to basic file system features, Btrfs offers RAID and volume management, pooling, snapshots, checksums, compression and other features.</p>
<p>To use Btrfs, make sure you have <code class="docutils literal notranslate"><span class="pre">btrfs-progs</span></code> installed on your machine.</p>
<section id="terminology">
<h2>Terminology<a class="headerlink" href="#terminology" title="Link to this heading">¶</a></h2>
<p>A Btrfs file system can have <em>subvolumes</em>, which are named binary subtrees of the main tree of the file system with their own independent file and directory hierarchy.
A <em>Btrfs snapshot</em> is a special type of subvolume that captures a specific state of another subvolume.
Snapshots can be read-write or read-only.</p>
</section>
<section id="btrfs-driver-in-lxd">
<h2><code class="docutils literal notranslate"><span class="pre">btrfs</span></code> driver in LXD<a class="headerlink" href="#btrfs-driver-in-lxd" title="Link to this heading">¶</a></h2>
<p>The <code class="docutils literal notranslate"><span class="pre">btrfs</span></code> driver in LXD uses a subvolume per instance, image and snapshot.
When creating a new entity (for example, launching a new instance), it creates a Btrfs snapshot.</p>
<p>Btrfs doesn’t natively support storing block devices.
Therefore, when using Btrfs for VMs, LXD creates a big file on disk to store the VM.
This approach is not very efficient and might cause issues when creating snapshots.</p>
<p>Btrfs can be used as a storage backend inside a container in a nested LXD environment.
In this case, the parent container itself must use Btrfs.
Note, however, that the nested LXD setup does not inherit the Btrfs quotas from the parent (see <a class="reference internal" href="#storage-btrfs-quotas"><span class="std std-ref">Quotas</span></a> below).</p>
<section id="quotas">
<span id="storage-btrfs-quotas"></span><h3>Quotas<a class="headerlink" href="#quotas" title="Link to this heading">¶</a></h3>
<p>Btrfs supports storage quotas via qgroups.
Btrfs qgroups are hierarchical, but new subvolumes will not automatically be added to the qgroups of their parent subvolumes.
This means that users can trivially escape any quotas that are set.
Therefore, if strict quotas are needed, you should consider using a different storage driver (for example, ZFS with <code class="docutils literal notranslate"><span class="pre">refquota</span></code> or LVM with Btrfs on top).</p>
<p>When using quotas, you must take into account that Btrfs extents are immutable.
When blocks are written, they end up in new extents.
The old extents remain until all their data is dereferenced or rewritten.
This means that a quota can be reached even if the total amount of space used by the current files in the subvolume is smaller than the quota.</p>
<div class="admonition note">
<p class="admonition-title">Note</p>
<p>This issue is seen most often when using VMs on Btrfs, due to the random I/O nature of using raw disk image files on top of a Btrfs subvolume.</p>
<p>Therefore, you should never use VMs with Btrfs storage pools.</p>
<p>If you really need to use VMs with Btrfs storage pools, set the instance root disk’s <a class="configref reference internal" href="../devices_disk/#device-disk-device-conf:size.state"><code class="docutils literal notranslate"><span class="pre">size.state</span></code></a> property to twice the size of the root disk’s size.
This configuration allows all blocks in the disk image file to be rewritten without reaching the qgroup quota.
Setting the <a class="configref reference internal" href="#storage-btrfs-pool-conf:btrfs.mount_options"><code class="docutils literal notranslate"><span class="pre">btrfs.mount_options</span></code></a> storage pool option to <code class="docutils literal notranslate"><span class="pre">compress-force</span></code> can also avoid this scenario, because a side effect of enabling compression is to reduce the maximum extent size such that block rewrites don’t cause as much storage to be double-tracked.
However, this is a storage pool option, and it therefore affects all volumes on the pool.</p>
</div>
</section>
</section>
<section id="configuration-options">
<h2>Configuration options<a class="headerlink" href="#configuration-options" title="Link to this heading">¶</a></h2>
<p>The following configuration options are available for storage pools that use the <code class="docutils literal notranslate"><span class="pre">btrfs</span></code> driver and for storage volumes in these pools.</p>
<section id="storage-pool-configuration">
<span id="storage-btrfs-pool-config"></span><h3>Storage pool configuration<a class="headerlink" href="#storage-pool-configuration" title="Link to this heading">¶</a></h3>
<div class="configoption docutils container" id="storage-btrfs-pool-conf:btrfs.mount_options">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">btrfs.mount_options</span></code></span><span class="shortdesc"><p>Mount options for block devices</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-pool-conf:btrfs.mount_options"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">btrfs.mount_options</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p><code class="docutils literal notranslate"><span class="pre">user_subvol_rm_allowed</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-pool-conf:size">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">size</span></code></span><span class="shortdesc"><p>Size of the storage pool (for loop-based pools)</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-pool-conf:size"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">size</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>auto (20% of free disk space, >= 5 GiB and <= 30 GiB)</p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>local</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>When creating loop-based pools, specify the size in bytes (<a class="reference internal" href="../instance_units/#instances-limit-units"><span class="std std-ref">suffixes</span></a> are supported).
You can increase the size to grow the storage pool.</p>
<p>The default (<code class="docutils literal notranslate"><span class="pre">auto</span></code>) creates a storage pool that uses 20% of the free disk space,
with a minimum of 5 GiB and a maximum of 30 GiB.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-pool-conf:source">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">source</span></code></span><span class="shortdesc"><p>Path to an existing block device, loop file, or Btrfs subvolume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-pool-conf:source"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">source</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>local</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-pool-conf:source.recover">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">source.recover</span></code></span><span class="shortdesc"><p>Whether to recover an existing <code class="docutils literal notranslate"><span class="pre">source</span></code></p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-pool-conf:source.recover"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">source.recover</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>bool</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p><code class="docutils literal notranslate"><span class="pre">false</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>local</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Set this option to true to recover an existing source which was previously created by LXD.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-pool-conf:source.wipe">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">source.wipe</span></code></span><span class="shortdesc"><p>Whether to wipe the block device before creating the pool</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-pool-conf:source.wipe"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">source.wipe</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>bool</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p><code class="docutils literal notranslate"><span class="pre">false</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>local</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Set this option to <code class="docutils literal notranslate"><span class="pre">true</span></code> to wipe the block device specified in <code class="docutils literal notranslate"><span class="pre">source</span></code>
prior to creating the storage pool.</p>
</div>
</div>
<div class="admonition tip">
<p class="admonition-title">Tip</p>
<p>In addition to these configurations, you can also set default values for the storage volume configurations. See <a class="reference internal" href="../../howto/storage_volumes/#storage-configure-vol-default"><span class="std std-ref">Configure default values for storage volumes</span></a>.</p>
</div>
</section>
<section id="storage-volume-configuration">
<h3>Storage volume configuration<a class="headerlink" href="#storage-volume-configuration" title="Link to this heading">¶</a></h3>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:security.shared">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">security.shared</span></code></span><span class="shortdesc"><p>Enable volume sharing</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:security.shared"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">security.shared</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>bool</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.security.shared</span></code> or <code class="docutils literal notranslate"><span class="pre">false</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>virtual-machine or custom block volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Enabling this option allows sharing the volume across multiple instances despite the possibility of data loss.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:security.shifted">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">security.shifted</span></code></span><span class="shortdesc"><p>Enable ID shifting overlay</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:security.shifted"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">security.shifted</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>bool</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.security.shifted</span></code> or <code class="docutils literal notranslate"><span class="pre">false</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>custom volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Enabling this option allows attaching the volume to multiple isolated instances.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:security.unmapped">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">security.unmapped</span></code></span><span class="shortdesc"><p>Disable ID mapping for the volume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:security.unmapped"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">security.unmapped</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>bool</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.security.unmappped</span></code> or <code class="docutils literal notranslate"><span class="pre">false</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>custom volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:size">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">size</span></code></span><span class="shortdesc"><p>Size/quota of the storage volume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:size"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">size</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.size</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>appropriate driver</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:snapshots.expiry">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">snapshots.expiry</span></code></span><span class="shortdesc"><p>When snapshots are to be deleted</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:snapshots.expiry"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">snapshots.expiry</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.snapshots.expiry</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>custom volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Specify an expression like <code class="docutils literal notranslate"><span class="pre">1M</span> <span class="pre">2H</span> <span class="pre">3d</span> <span class="pre">4w</span> <span class="pre">5m</span> <span class="pre">6y</span></code>.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:snapshots.pattern">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">snapshots.pattern</span></code></span><span class="shortdesc"><p>Template for the snapshot name</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:snapshots.pattern"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">snapshots.pattern</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.snapshots.pattern</span></code> or <code class="docutils literal notranslate"><span class="pre">snap%d</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>custom volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>You can specify a naming template that is used for scheduled snapshots and unnamed snapshots.</p>
<p>The <code class="docutils literal notranslate"><span class="pre">snapshots.pattern</span></code> option takes a Pongo2 template string to format the snapshot name.</p>
<p>To add a time stamp to the snapshot name, use the Pongo2 context variable <code class="docutils literal notranslate"><span class="pre">creation_date</span></code>.
Make sure to format the date in your template string to avoid forbidden characters in the snapshot name.
For example, set <code class="docutils literal notranslate"><span class="pre">snapshots.pattern</span></code> to <code class="docutils literal notranslate"><span class="pre">{{</span> <span class="pre">creation_date|date:'2006-01-02_15-04-05'</span> <span class="pre">}}</span></code> to name the snapshots after their time of creation, down to the precision of a second.</p>
<p>Another way to avoid name collisions is to use the placeholder <code class="docutils literal notranslate"><span class="pre">%d</span></code> in the pattern.
For the first snapshot, the placeholder is replaced with <code class="docutils literal notranslate"><span class="pre">0</span></code>.
For subsequent snapshots, the existing snapshot names are taken into account to find the highest number at the placeholder’s position.
This number is then incremented by one for the new name.</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:snapshots.schedule">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">snapshots.schedule</span></code></span><span class="shortdesc"><p>Schedule for automatic volume snapshots</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:snapshots.schedule"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">snapshots.schedule</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">snapshots.schedule</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>custom volume</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
<p>Specify either a cron expression (<code class="docutils literal notranslate"><span class="pre"><minute></span> <span class="pre"><hour></span> <span class="pre"><dom></span> <span class="pre"><month></span> <span class="pre"><dow></span></code>), a comma-separated list of schedule aliases (<code class="docutils literal notranslate"><span class="pre">@hourly</span></code>, <code class="docutils literal notranslate"><span class="pre">@daily</span></code>, <code class="docutils literal notranslate"><span class="pre">@midnight</span></code>, <code class="docutils literal notranslate"><span class="pre">@weekly</span></code>, <code class="docutils literal notranslate"><span class="pre">@monthly</span></code>, <code class="docutils literal notranslate"><span class="pre">@annually</span></code>, <code class="docutils literal notranslate"><span class="pre">@yearly</span></code>), or leave empty to disable automatic snapshots (the default).</p>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:volatile.devlxd.owner">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">volatile.devlxd.owner</span></code></span><span class="shortdesc"><p>The ID of the DevLXD identity which owns the volume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:volatile.devlxd.owner"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">volatile.devlxd.owner</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>DevLXD owner identity ID</p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:volatile.idmap.last">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">volatile.idmap.last</span></code></span><span class="shortdesc"><p>JSON-serialized UID/GID map that has been applied to the volume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:volatile.idmap.last"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">volatile.idmap.last</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>filesystem</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:volatile.idmap.next">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">volatile.idmap.next</span></code></span><span class="shortdesc"><p>JSON-serialized UID/GID map that has been applied to the volume</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:volatile.idmap.next"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">volatile.idmap.next</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>filesystem</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="configoption docutils container" id="storage-btrfs-volume-conf:volatile.uuid">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">volatile.uuid</span></code></span><span class="shortdesc"><p>The volume’s UUID</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-volume-conf:volatile.uuid"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">volatile.uuid</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>random UUID</p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>global</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</section>
<section id="storage-bucket-configuration">
<h3>Storage bucket configuration<a class="headerlink" href="#storage-bucket-configuration" title="Link to this heading">¶</a></h3>
<p>To enable storage buckets for local storage pool drivers and allow applications to access the buckets via the S3 protocol, you must configure the <a class="configref reference internal" href="../../server/#server-core:core.storage_buckets_address"><code class="docutils literal notranslate"><span class="pre">core.storage_buckets_address</span></code></a> server setting.</p>
<div class="configoption docutils container" id="storage-btrfs-bucket-conf:size">
<div class="basicinfo docutils container">
<span class="key"><code class="docutils literal notranslate"><span class="pre">size</span></code></span><span class="shortdesc"><p>Size/quota of the storage bucket</p>
</span><span class="anchor"><a class="reference external" href="#storage-btrfs-bucket-conf:size"><i class="icon"><svg><use href="#svg-arrow-right"></use></svg></i></a></span></div>
<div class="details docutils container">
<div class="table-wrapper fields docutils container">
<table class="fields docutils align-default">
<tbody>
<tr class="row-odd"><td><strong>Key: </strong></td>
<td><code class="docutils literal notranslate"><span class="pre">size</span></code></td>
</tr>
<tr class="row-even"><td><strong>Type: </strong></td>
<td><span class="ignoreP"><p>string</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Default: </strong></td>
<td><span class="ignoreP"><p>same as <code class="docutils literal notranslate"><span class="pre">volume.size</span></code></p>
</span></td>
</tr>
<tr class="row-even"><td><strong>Condition: </strong></td>
<td><span class="ignoreP"><p>appropriate driver</p>
</span></td>
</tr>
<tr class="row-odd"><td><strong>Scope: </strong></td>
<td><span class="ignoreP"><p>local</p>
</span></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</section>
</section>
</section>
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Contents
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<ul>
<li><a class="reference internal" href="#">Btrfs - <code class="docutils literal notranslate"><span class="pre">btrfs</span></code></a><ul>
<li><a class="reference internal" href="#terminology">Terminology</a></li>
<li><a class="reference internal" href="#btrfs-driver-in-lxd"><code class="docutils literal notranslate"><span class="pre">btrfs</span></code> driver in LXD</a><ul>
<li><a class="reference internal" href="#quotas">Quotas</a></li>
</ul>
</li>
<li><a class="reference internal" href="#configuration-options">Configuration options</a><ul>
<li><a class="reference internal" href="#storage-pool-configuration">Storage pool configuration</a></li>
<li><a class="reference internal" href="#storage-volume-configuration">Storage volume configuration</a></li>
<li><a class="reference internal" href="#storage-bucket-configuration">Storage bucket configuration</a></li>
</ul>
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</ul>
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