Menu="Main:2"
Title="Cache Devices"
Cond="($var['fsState']=='Stopped' || $var['cacheSbNumDisks'])"
---
<?PHP
/* Copyright 2005-2016, Lime Technology
 * Copyright 2012-2016, Bergware International.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2,
 * as published by the Free Software Foundation.
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 */
?>
<script>
function cache_status() {
  $.post('/webGui/include/DeviceList.php',{path:'<?=$path?>',device:'cache'},function(data) {
    if (data) $('#cache_device').html(data);
<?if ($update && $var['fsState']=='Started'):?>
<?if ($tabbed):?>
    if ($('#tab2').is(':checked')) timer = setTimeout(cache_status,<?=abs($display['refresh'])?>);
<?else:?>
    setTimeout(cache_status,<?=abs($display['refresh'])?>);
<?endif;?>
<?endif;?>
  });
}
<?if ($update && $var['fsState']=='Started' && $tabbed):?>
$('#tab2').bind({click:function() {clearTimeout(timer); cache_status();}});
<?endif;?>

cache_status();
</script>

<table class="disk_status <?=($var['fsState']=='Stopped'?'small':$display['view']).' '.$display['align']?>">
<thead><tr><td>Device</td><td>Identification</td><td>Temp.</td><td>Reads</td><td>Writes</td><td>Errors</td><td>FS</td><td>Size</td><td>Used</td><td>Free</td><td>View</td></tr></thead>
<tbody id="cache_device">
<?
foreach ($disks as $disk):
  if ($disk['type']=='Cache') echo "<tr><td colspan='11'>&nbsp;</td></tr>";
endforeach;
?>
</tbody>
</table>

> **Colored Status Indicator** the significance of the color indicator at the beginning of each line in *Cache Devices* is as follows:
>
> <img src='/webGui/images/green-on.png' class='icon'>Normal operation, device is active.
>
> <img src='/webGui/images/green-blink.png' class='icon'>Device is in standby mode (spun-down).
>
> <img src='/webGui/images/blue-on.png' class='icon'>New device.
>
> <img src='/webGui/images/grey-off.png' class='icon'>No device present, position is empty.
>
> **Cache** is a device, or device pool, *outside* the unRAID array.  It may be exported for network access just
> like an Array device.  Being outside the unRAID array results in significantly faster write access.
>
> There are two ways to configure the Cache:
>
> 1. As a single device, or
> 2. As a multi-device pool.
>
> When configured as a single device you may format the device using any supported file system (btrfs, reiserfs,
> or xfs).  This configuration offers the highest performance, but at the cost of no data protection - if the
> single Cache device fails all data contained on it may be lost.
>
> When configured as a multi-device pool, unRAID OS will automatically select *btrfs-raid1* format (for both data
> and meta-data).  btrfs permits any number of devices to be added to the pool and each copy of data is guaranteed
> to be written to two different devices.  Hence the pool can withstand a single-disk failure without losing data.
>
> When [User Shares](/Settings/ShareSettings) are enabled, user shares may be configured to
> automatically make use of the Cache in order to
> speed up writes.  A special background process called the *mover* can be scheduled to run
> periodically to move user share files off the Cache and onto the Array.

<?if ($var['fsState'] == "Stopped"):?>
<div></div>
> **Slots** select the number of device slots in your server designated for Cache devices.
<?endif;?>