Differences

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--- omv6:omv6_plugins:mergerfs [2023/05/09 01:21] – [Setup] crashtest
+++ omv6:omv6_plugins:mergerfs [2024/07/09 01:38] (current) – [Existing Path - Most Free Space] crashtest
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-{{indexmenu_n>5}}
+{{indexmenu_n>8}}
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 <html><center><b>The MergerFS Plugin For OMV6</b></center></html>
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 <html><center><b>Most Free Space</b> is a single directive that performs exactly what it suggests.</center></html>
-<html><center>If dissimilar drive sizes are used, <b>Most Free Space</b> will direct more data toward the largest drive when compared to smaller member drives.</center></html>
+<html><center>If dissimilar drive sizes are used, <b>Most Free Space</b> will direct data toward the largest drive.</center></html>
 {{ ::mergerfs-04.jpg?600 |}}
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-<html><center>Drives are filled by "percentage used" which will distribute files among all drives in an even manner.</center></html>
-<html><center>With the added advantage of being able to use different sized drives, this storage policy roughly mimics the storage distribution attribute of RAID5.</center></html>
+<html><center>When the space remaining between all drives is roughly the same, data will be distributed equally among all member drives.</center></html>
 {{ ::mergerfs-05.jpg?600 |}}
+<html><center>With the added advantage of being able to use different sized drives, the <b>Most Free Space</b> storage policy roughly mimics the storage distribution attribute of RAID5.</center></html>
+<html><center>Typically, the <b>Most Free Space</b> storage policy is a good choice when merged drives will be populated with libraries of large video and music files.</center></html>
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 Note, in the following, the distribution of paths among member drives.  Once a new folder is created, on a drive with the **Most Free Space**, a path is established.  According to the first directive all subsequently saved files will go to the **Existing Path**.
+----
+The issue that the **Existing Path** directive can create is due to the difference in files sizes.  When compared to documents or even picture files, music and video files can be massive, ranging from 100's of megabytes to several gigabytes.  If users increasingly add large video files to a MergerFS array, the **Existing Path** directive can easily fill one drive of the array completely.  At that point, the array will stop accepting files destined for the full drive.\\
 {{ ::mergerfs-06.jpg?600 |}}
-The issue that this can create is due to the difference in files sizes.  When compared to documents or even picture files, video files can be massive ranging from 100's of megabytes to several gigabytes.  If users increasingly add large video files to a MergerFS array, the **Existing Path** directive can easily fill one drive of the array completely.  At that point, the array will stop accepting files destined for the full drive.  This issue can be corrected using the **Balance Pool** Tool {{::mergerfs-07-balance_pool.jpg?30|}} which will spread data among the array's member drives.\\
+This issue can be corrected using the **Balance Pool** Tool {{::mergerfs-07-balance_pool.jpg?30|}} which will redistribute data among the array's member drives.\\
+<html>
+<body>
+  <table width="100%" border="0">
+    <tr>
+      <td colspan="2" style="background-color:#69A5FF;height:30px;">
+        <strong><span style="color:#FFFFFF;font-size:110%;">&#160; Note For users who may test MergerFS using small virtual drives:</span></strong>
+      </td>
+    </tr>
+    <tr>
+      <td style="background-color:#E6FEFF;height:25px;width:380px;">
+        MergerFS balances drives to within 2% fill of all member drives. Populating tiny 8 to 10GB virtual drives with video files that may be as large
+as 1 or 2GB each (which is roughly 10 to 20% of a member drive) may trigger "ping pong" file copying between drives.  Filling tiny drives with huge files makes the "within 2%" balance goal, of the algorithm, unachievable.  When testing MergerFS using small virtual drives, use small files such as documents, pictures, or small audio files.
+    </tr>
+  </table>
+</body>
+</html>
+\\
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-==== Notes ====
+===== Replacing a Failed MergerFS Drive =====
+Since MergerFS is frequently used with SnapRAID, replacing a failed MergerFS Drive is part of the final step in recovering a MergerFS / SnapRAID array, as detailed -> [[https://wiki.omv-extras.org/doku.php?id=omv6:omv6_plugins:snapraid#replacing_a_failed_drive_in_mergerfs|here]].
+===== Notes =====
   * MergerFS, by design, distributes folders and files between multiple hard drives.  Accordingly, to gain the ability to recover a hard drive along with other recovery features, users are strongly encouraged to consider the addition of **SNAPRAID** to protect a MergerFS array.  Further, -> [[https://wiki.omv-extras.org/doku.php?id=omv6:utilities_maint_backup#backing_up_data|full data backup]] is recommended for recovery from data disasters.
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 - MergerFS does not fully support COW (Copy on Write) filesystems like ZFS or BTRFS.  When creating a MergerFS array, simple filesystems like EXT4 or XFS are recommended.\\
 - While MergerFS may work with NTFS or FAT (Windows filesystems) when using a package like ntfs-3g, they are non-POSIX file systems.  File and folder permission issues may result in MergerFS and in OMV.  For the best use experience, Linux native filesystems like EXT4 or XFS are recommended.\\
+\\