Difference between revisions of "Btrfs/en"

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=== btrfs filesystem du ===

Here the full scope of btrfs' difference becomes visible. When btrfs takes snapshots, many files are contained unchanged in several snapshots, but only take up space in the file system once. At the same time, there can be the same(!) file with different content and size in different snapshots.

It is therefore not enough to simply add up the size of all files in a path to determine the '''space consumption''' in the file system.

For each file, it must be determined how large it is and whether all or part of it is shared with other subvolumes. Since btrfs has to read a lot of metadata for this, it can take a '''long time''' to display the results:

Total Exclusive Set shared Filename

8.11TiB 6.23GiB 215.76GiB /home

{{BoxInfo|Total|The sum of all files, as "du" would display them in a conventional file system. This is how much space a conventional file system would use to store these files (and all the necessary copies).}}

{{BoxInfo|Exclusive|The sum of the files that "only" occur in one of the subvolumes and are not shared with other subvolumes}}

{{BoxInfo|Set shared|The sum of files shared with other subvolumes}}

{{BoxInfo|Exclusive + Set shared|This is the actual space used in the file system}}

=== btrfs filesystem show ===

=== btrfs filesystem usage ===

@@ Line 428: / Line 428: @@
 === btrfs filesystem du ===
+Here the full scope of btrfs' difference becomes visible. When btrfs takes snapshots, many files are contained unchanged in several snapshots, but only take up space in the file system once. At the same time, there can be the same(!) file with different content and size in different snapshots.
+It is therefore not enough to simply add up the size of all files in a path to determine the '''space consumption''' in the file system.
+For each file, it must be determined how large it is and whether all or part of it is shared with other subvolumes. Since btrfs has to read a lot of metadata for this, it can take a '''long time''' to display the results:
+{{RootCmd|command=btrfs filesystem du -s /home}}
+     Total   Exclusive  Set shared  Filename
+.11TiB     6.23GiB   215.76GiB  /home
+{{BoxInfo|Total|The sum of all files, as "du" would display them in a conventional file system. This is how much space a conventional file system would use to store these files (and all the necessary copies).}}
+{{BoxInfo|Exclusive|The sum of the files that "only" occur in one of the subvolumes and are not shared with other subvolumes}}
+{{BoxInfo|Set shared|The sum of files shared with other subvolumes}}
+{{BoxInfo|Exclusive + Set shared|This is the actual space used in the file system}}
 === btrfs filesystem show ===
 === btrfs filesystem usage ===