Adjust Btrfs snapshot paths so that Borg 1.x gets file cache hits when backing them up (#1206).

Reviewed-on: https://projects.torsion.org/borgmatic-collective/borgmatic/pulls/1206

NEWS

@@ -2,6 +2,8 @@
  * #1054: Allow the Btrfs hook to create and delete snapshots even when running
    as a non-root user. See the documentation for more information:
    https://torsion.org/borgmatic/reference/configuration/data-sources/btrfs/#non-root-user
+ * #1122: To prevent the user from inadvertently excluding the "bootstrap" action's manifest, always
+   error and exit when the borgmatic runtime directory overlaps with the configured excludes.
  * #1179: Add a "file_list_format" option for setting the "list" action's output format and an
    "archive_list_format" option for setting the "repo-list" action's format.
  * #1192: Fix for over-aggressive deduplication of source directories that contain the borgmatic
@@ -24,8 +26,8 @@
  * #1203: Fix that errors and exits when the borgmatic runtime directory is partially excluded by
    configured excludes. Previously, borgmatic only errored when the runtime directory was completely
    excluded.
- * #1122: To prevent the user from inadvertently excluding the "bootstrap" action's manifest, always
-   error and exit when the borgmatic runtime directory overlaps with the configured excludes.
+ * #1206: Adjust Btrfs snapshot paths so that Borg 1.x gets file cache hits when backing them up,
+   improving performance.
  * Update the sample systemd timer with a shorter random delay when catching up on a missed run.
 
 2.0.12

borgmatic/hooks/data_source/btrfs.py

@@ -171,7 +171,7 @@ def get_subvolumes(btrfs_command, patterns):
     return tuple(sorted(subvolumes, key=lambda subvolume: subvolume.path))
 
 
-BORGMATIC_SNAPSHOT_PREFIX = '.borgmatic-snapshot-'
+BORGMATIC_SNAPSHOT_PREFIX = '.borgmatic-snapshot'
 
 
 def make_snapshot_path(subvolume_path):
@@ -180,7 +180,7 @@ def make_snapshot_path(subvolume_path):
     '''
     return os.path.join(
         subvolume_path,
-        f'{BORGMATIC_SNAPSHOT_PREFIX}{os.getpid()}',
+        f'{BORGMATIC_SNAPSHOT_PREFIX}',
         # Included so that the snapshot ends up in the Borg archive at the "original" subvolume path.
     ) + subvolume_path.rstrip(os.path.sep)
 
@@ -193,16 +193,16 @@ def make_snapshot_exclude_pattern(subvolume_path):  # pragma: no cover
     directory within the snapshot itself. For instance, if you have a Btrfs subvolume at /mnt and
     make a snapshot of it at:
 
-        /mnt/.borgmatic-snapshot-1234/mnt
+        /mnt/.borgmatic-snapshot/mnt
 
     ... then the snapshot itself will have an empty directory at:
 
-        /mnt/.borgmatic-snapshot-1234/mnt/.borgmatic-snapshot-1234
+        /mnt/.borgmatic-snapshot/mnt/.borgmatic-snapshot
 
     So to prevent that from ending up in the Borg archive, this function produces an exclude pattern
     to exclude that path.
     '''
-    snapshot_directory = f'{BORGMATIC_SNAPSHOT_PREFIX}{os.getpid()}'
+    snapshot_directory = f'{BORGMATIC_SNAPSHOT_PREFIX}'
 
     return borgmatic.borg.pattern.Pattern(
         os.path.join(
@@ -235,7 +235,7 @@ def make_borg_snapshot_pattern(subvolume_path, pattern):
 
     rewritten_path = initial_caret + os.path.join(
         subvolume_path,
-        f'{BORGMATIC_SNAPSHOT_PREFIX}{os.getpid()}',
+        f'{BORGMATIC_SNAPSHOT_PREFIX}',
         # Use the Borg 1.4+ "slashdot" hack to prevent the snapshot path prefix from getting
         # included in the archive—but only if there's not already a slashdot hack present in the
         # pattern.

docs/reference/configuration/data-sources/btrfs.md

@@ -60,7 +60,7 @@ Additionally, borgmatic rewrites the snapshot file paths so that they appear at
 their original subvolume locations in a Borg archive. For instance, if your
 subvolume path is `/var/subvolume`, then the snapshotted files will appear in an
 archive at `/var/subvolume` as well—even if borgmatic has to mount the snapshot
-somewhere in `/var/subvolume/.borgmatic-snapshot-1234/` to perform the backup.
+somewhere in `/var/subvolume/.borgmatic-snapshot/` to perform the backup.
 
 <span class="minilink minilink-addedin">With Borg version 1.2 and
 earlier</span>Snapshotted files are instead stored at a path dependent on the
@@ -70,26 +70,24 @@ temporary snapshot directory in use at the time the archive was created, as Borg
 
 ## Performance
 
-<span class="minilink minilink-addedin">With Borg version 1.x</span> Because of
-the way that Btrfs snapshot paths change from one borgmatic invocation to the
-next, the [Borg file
+<span class="minilink minilink-addedin">New in borgmatic version 2.0.13, with
+Borg version 1.x</span> borgmatic uses consistent snapshot paths between
+invocations, so Btrfs snapshots are cached correctly. No configuration is
+necessary.
+
+<span class="minilink minilink-addedin">Prior to borgmatic version 2.0.13, with
+Borg version 1.x</span> Because of the way that Btrfs snapshot paths change from
+one borgmatic invocation to the next, the [Borg file
 cache](https://borgbackup.readthedocs.io/en/stable/internals/data-structures.html#cache)
-will never get cache hits on snapshotted files. This makes backing up Btrfs
+never gets cache hits on snapshotted files. This makes backing up Btrfs
 snapshots a little slower than non-snapshotted files that have consistent paths.
-**It is also not possible to mitigate cache misses**, as the Btrfs hook uses
-snapshot paths which change between borgmatic invocations, and the snapshots
-are located outside the [runtime
-directory](https://torsion.org/borgmatic/reference/configuration/runtime-directory/),
-contrary to
-[ZFS](https://torsion.org/borgmatic/reference/configuration/data-sources/zfs/#performance)
-and
-[LVM](https://torsion.org/borgmatic/reference/configuration/data-sources/lvm/#performance).
+If this is an issue for you, upgrade to borgmatic to 2.0.13+.
 
 <span class="minilink minilink-addedin">With Borg version 2.x</span> Even
-snapshotted files should get cache hits, because Borg 2.x is smarter about how
-it looks up file paths in its cache—it constructs the cache key with the path
-*as it's seen in the archive* (which is consistent across runs) rather than the
-full absolute source path (which changes).
+snapshotted files get cache hits, because Borg 2.x is smarter about how it looks
+up file paths in its cache—it constructs the cache key with the path *as it's
+seen in the archive* (which is consistent across runs) rather than the full
+absolute source path (which changes).
 
 
 ## systemd settings

tests/integration/hooks/data_source/test_btrfs.py

@@ -24,16 +24,15 @@ def test_dump_data_sources_snapshots_each_subvolume_and_updates_patterns():
             module.Subvolume('/mnt/subvol2', contained_patterns=(Pattern('/mnt/subvol2'),)),
         ),
     )
-    flexmock(module.os).should_receive('getpid').and_return(1234)
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         'btrfs',
         '/mnt/subvol1',
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).once()
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         'btrfs',
         '/mnt/subvol2',
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).once()
 
     assert (
@@ -50,19 +49,19 @@ def test_dump_data_sources_snapshots_each_subvolume_and_updates_patterns():
 
     assert patterns == [
         Pattern(
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2/.borgmatic-snapshot-1234',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
         Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
         Pattern('/foo'),
-        Pattern('/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1'),
-        Pattern('/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1/.cache', Pattern_type.EXCLUDE),
-        Pattern('/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2'),
+        Pattern('/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1'),
+        Pattern('/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1/.cache', Pattern_type.EXCLUDE),
+        Pattern('/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2'),
     ]
     assert config == {
         'btrfs': {},

tests/unit/hooks/data_source/test_btrfs.py

@@ -331,16 +331,14 @@ def test_get_subvolumes_skips_non_config_patterns():
 @pytest.mark.parametrize(
     'subvolume_path,expected_snapshot_path',
     (
-        ('/foo/bar', '/foo/bar/.borgmatic-snapshot-1234/foo/bar'),
-        ('/', '/.borgmatic-snapshot-1234'),
+        ('/foo/bar', '/foo/bar/.borgmatic-snapshot/foo/bar'),
+        ('/', '/.borgmatic-snapshot'),
     ),
 )
 def test_make_snapshot_path_includes_stripped_subvolume_path(
     subvolume_path,
     expected_snapshot_path,
 ):
-    flexmock(module.os).should_receive('getpid').and_return(1234)
-
     assert module.make_snapshot_path(subvolume_path) == expected_snapshot_path
 
 
@@ -350,14 +348,14 @@ def test_make_snapshot_path_includes_stripped_subvolume_path(
         (
             '/foo/bar',
             Pattern('/foo/bar/baz'),
-            Pattern('/foo/bar/.borgmatic-snapshot-1234/./foo/bar/baz'),
+            Pattern('/foo/bar/.borgmatic-snapshot/./foo/bar/baz'),
         ),
-        ('/foo/bar', Pattern('/foo/bar'), Pattern('/foo/bar/.borgmatic-snapshot-1234/./foo/bar')),
+        ('/foo/bar', Pattern('/foo/bar'), Pattern('/foo/bar/.borgmatic-snapshot/./foo/bar')),
         (
             '/foo/bar',
             Pattern('^/foo/bar', Pattern_type.INCLUDE, Pattern_style.REGULAR_EXPRESSION),
             Pattern(
-                '^/foo/bar/.borgmatic-snapshot-1234/./foo/bar',
+                '^/foo/bar/.borgmatic-snapshot/./foo/bar',
                 Pattern_type.INCLUDE,
                 Pattern_style.REGULAR_EXPRESSION,
             ),
@@ -366,17 +364,17 @@ def test_make_snapshot_path_includes_stripped_subvolume_path(
             '/foo/bar',
             Pattern('/foo/bar', Pattern_type.INCLUDE, Pattern_style.REGULAR_EXPRESSION),
             Pattern(
-                '/foo/bar/.borgmatic-snapshot-1234/./foo/bar',
+                '/foo/bar/.borgmatic-snapshot/./foo/bar',
                 Pattern_type.INCLUDE,
                 Pattern_style.REGULAR_EXPRESSION,
             ),
         ),
-        ('/', Pattern('/foo'), Pattern('/.borgmatic-snapshot-1234/./foo')),
-        ('/', Pattern('/'), Pattern('/.borgmatic-snapshot-1234/./')),
+        ('/', Pattern('/foo'), Pattern('/.borgmatic-snapshot/./foo')),
+        ('/', Pattern('/'), Pattern('/.borgmatic-snapshot/./')),
         (
             '/foo/bar',
             Pattern('/foo/bar/./baz'),
-            Pattern('/foo/bar/.borgmatic-snapshot-1234/foo/bar/./baz'),
+            Pattern('/foo/bar/.borgmatic-snapshot/foo/bar/./baz'),
         ),
     ),
 )
@@ -385,8 +383,6 @@ def test_make_borg_snapshot_pattern_includes_slashdot_hack_and_stripped_pattern_
     pattern,
     expected_pattern,
 ):
-    flexmock(module.os).should_receive('getpid').and_return(1234)
-
     assert module.make_borg_snapshot_pattern(subvolume_path, pattern) == expected_pattern
 
 
@@ -400,26 +396,26 @@ def test_dump_data_sources_snapshots_each_subvolume_and_replaces_patterns():
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     )
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         'btrfs',
         '/mnt/subvol1',
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).once()
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         'btrfs',
         '/mnt/subvol2',
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).once()
     flexmock(module).should_receive('make_snapshot_exclude_pattern').with_args(
         '/mnt/subvol1',
     ).and_return(
         Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -428,7 +424,7 @@ def test_dump_data_sources_snapshots_each_subvolume_and_replaces_patterns():
         '/mnt/subvol2',
     ).and_return(
         Pattern(
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2/.borgmatic-snapshot-1234',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -436,16 +432,16 @@ def test_dump_data_sources_snapshots_each_subvolume_and_replaces_patterns():
     flexmock(module).should_receive('make_borg_snapshot_pattern').with_args(
         '/mnt/subvol1',
         object,
-    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1'))
+    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1'))
     flexmock(module).should_receive('make_borg_snapshot_pattern').with_args(
         '/mnt/subvol2',
         object,
-    ).and_return(Pattern('/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2'))
+    ).and_return(Pattern('/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2'))
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('replace_pattern').with_args(
         object,
         Pattern('/mnt/subvol1'),
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
             source=module.borgmatic.borg.pattern.Pattern_source.HOOK,
         ),
     ).once()
@@ -453,14 +449,14 @@ def test_dump_data_sources_snapshots_each_subvolume_and_replaces_patterns():
         object,
         Pattern('/mnt/subvol2'),
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
             source=module.borgmatic.borg.pattern.Pattern_source.HOOK,
         ),
     ).once()
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('inject_pattern').with_args(
         object,
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -468,7 +464,7 @@ def test_dump_data_sources_snapshots_each_subvolume_and_replaces_patterns():
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('inject_pattern').with_args(
         object,
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2/.borgmatic-snapshot-1234',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -498,18 +494,18 @@ def test_dump_data_sources_uses_custom_btrfs_command_in_commands():
         (module.Subvolume('/mnt/subvol1', contained_patterns=(Pattern('/mnt/subvol1'),)),),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     )
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         '/usr/local/bin/btrfs',
         '/mnt/subvol1',
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).once()
     flexmock(module).should_receive('make_snapshot_exclude_pattern').with_args(
         '/mnt/subvol1',
     ).and_return(
         Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -517,19 +513,19 @@ def test_dump_data_sources_uses_custom_btrfs_command_in_commands():
     flexmock(module).should_receive('make_borg_snapshot_pattern').with_args(
         '/mnt/subvol1',
         object,
-    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1'))
+    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1'))
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('replace_pattern').with_args(
         object,
         Pattern('/mnt/subvol1'),
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
             source=module.borgmatic.borg.pattern.Pattern_source.HOOK,
         ),
     ).once()
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('inject_pattern').with_args(
         object,
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -565,18 +561,18 @@ def test_dump_data_sources_with_findmnt_command_warns():
         (module.Subvolume('/mnt/subvol1', contained_patterns=(Pattern('/mnt/subvol1'),)),),
     ).once()
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     )
     flexmock(module).should_receive('snapshot_subvolume').with_args(
         'btrfs',
         '/mnt/subvol1',
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).once()
     flexmock(module).should_receive('make_snapshot_exclude_pattern').with_args(
         '/mnt/subvol1',
     ).and_return(
         Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -584,19 +580,19 @@ def test_dump_data_sources_with_findmnt_command_warns():
     flexmock(module).should_receive('make_borg_snapshot_pattern').with_args(
         '/mnt/subvol1',
         object,
-    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1'))
+    ).and_return(Pattern('/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1'))
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('replace_pattern').with_args(
         object,
         Pattern('/mnt/subvol1'),
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
             source=module.borgmatic.borg.pattern.Pattern_source.HOOK,
         ),
     ).once()
     flexmock(module.borgmatic.hooks.data_source.config).should_receive('inject_pattern').with_args(
         object,
         module.borgmatic.borg.pattern.Pattern(
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1/.borgmatic-snapshot-1234',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1/.borgmatic-snapshot',
             Pattern_type.NO_RECURSE,
             Pattern_style.FNMATCH,
         ),
@@ -628,7 +624,7 @@ def test_dump_data_sources_with_dry_run_skips_snapshot_and_patterns_update():
         (module.Subvolume('/mnt/subvol1', contained_patterns=(Pattern('/mnt/subvol1'),)),),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     )
     flexmock(module).should_receive('snapshot_subvolume').never()
     flexmock(module).should_receive('make_snapshot_exclude_pattern').never()
@@ -684,91 +680,59 @@ def test_remove_data_source_dumps_deletes_snapshots():
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2',
     )
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol1/.borgmatic-*/mnt/subvol1')
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol2/.borgmatic-*/mnt/subvol2')
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol1/.borgmatic-*/mnt/subvol1',
     ).and_return(
-        (
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-            '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
-        ),
+        ('/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',),
     )
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol2/.borgmatic-*/mnt/subvol2',
     ).and_return(
-        (
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
-            '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
-        ),
+        ('/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',),
     )
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-    ).and_return(True)
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(True)
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
-    ).and_return(False)
-    flexmock(module).should_receive('delete_snapshot').with_args(
-        'btrfs',
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-    ).once()
     flexmock(module).should_receive('delete_snapshot').with_args(
         'btrfs',
-        '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).once()
     flexmock(module).should_receive('delete_snapshot').with_args(
         'btrfs',
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).once()
-    flexmock(module).should_receive('delete_snapshot').with_args(
-        'btrfs',
-        '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
-    ).never()
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234',
+        '/mnt/subvol1/.borgmatic-snapshot',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678',
+        '/mnt/subvol2/.borgmatic-snapshot',
     ).and_return(True)
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234',
-    ).and_return(True)
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678',
-    ).and_return(True)
-    flexmock(module.shutil).should_receive('rmtree').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234',
-    ).once()
     flexmock(module.shutil).should_receive('rmtree').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678',
+        '/mnt/subvol1/.borgmatic-snapshot',
     ).once()
     flexmock(module.shutil).should_receive('rmtree').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234',
+        '/mnt/subvol2/.borgmatic-snapshot',
     ).once()
-    flexmock(module.shutil).should_receive('rmtree').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678',
-    ).never()
 
     module.remove_data_source_dumps(
         hook_config=config['btrfs'],
@@ -846,50 +810,50 @@ def test_remove_data_source_dumps_with_dry_run_skips_deletes():
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2',
     )
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol1/.borgmatic-*/mnt/subvol1')
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol2/.borgmatic-*/mnt/subvol2')
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol1/.borgmatic-*/mnt/subvol1',
     ).and_return(
         (
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-            '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         ),
     )
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol2/.borgmatic-*/mnt/subvol2',
     ).and_return(
         (
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
-            '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         ),
     )
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(False)
     flexmock(module).should_receive('delete_snapshot').never()
     flexmock(module.shutil).should_receive('rmtree').never()
@@ -931,21 +895,21 @@ def test_remove_data_source_without_snapshots_skips_deletes():
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2',
     )
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol1/.borgmatic-*/mnt/subvol1')
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol2/.borgmatic-*/mnt/subvol2')
     flexmock(module.glob).should_receive('glob').and_return(())
@@ -971,50 +935,50 @@ def test_remove_data_source_dumps_with_delete_snapshot_file_not_found_error_bail
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2',
     )
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol1/.borgmatic-*/mnt/subvol1')
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol2/.borgmatic-*/mnt/subvol2')
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol1/.borgmatic-*/mnt/subvol1',
     ).and_return(
         (
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-            '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         ),
     )
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol2/.borgmatic-*/mnt/subvol2',
     ).and_return(
         (
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
-            '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         ),
     )
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(False)
     flexmock(module).should_receive('delete_snapshot').and_raise(FileNotFoundError)
     flexmock(module.shutil).should_receive('rmtree').never()
@@ -1037,50 +1001,50 @@ def test_remove_data_source_dumps_with_delete_snapshot_called_process_error_bail
         ),
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol1').and_return(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/./mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/./mnt/subvol1',
     )
     flexmock(module).should_receive('make_snapshot_path').with_args('/mnt/subvol2').and_return(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/./mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/./mnt/subvol2',
     )
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol1/.borgmatic-*/mnt/subvol1')
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/mnt/subvol2/.borgmatic-*/mnt/subvol2')
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol1/.borgmatic-*/mnt/subvol1',
     ).and_return(
         (
-            '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
-            '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
+            '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
         ),
     )
     flexmock(module.glob).should_receive('glob').with_args(
         '/mnt/subvol2/.borgmatic-*/mnt/subvol2',
     ).and_return(
         (
-            '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
-            '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
+            '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
         ),
     )
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-1234/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol1/.borgmatic-snapshot-5678/mnt/subvol1',
+        '/mnt/subvol1/.borgmatic-snapshot/mnt/subvol1',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-1234/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(True)
     flexmock(module.os.path).should_receive('isdir').with_args(
-        '/mnt/subvol2/.borgmatic-snapshot-5678/mnt/subvol2',
+        '/mnt/subvol2/.borgmatic-snapshot/mnt/subvol2',
     ).and_return(False)
     flexmock(module).should_receive('delete_snapshot').and_raise(
         module.subprocess.CalledProcessError(1, 'command', 'error'),
@@ -1103,40 +1067,29 @@ def test_remove_data_source_dumps_with_root_subvolume_skips_duplicate_removal():
     )
 
     flexmock(module).should_receive('make_snapshot_path').with_args('/').and_return(
-        '/.borgmatic-snapshot-1234',
+        '/.borgmatic-snapshot',
     )
 
     flexmock(module.borgmatic.config.paths).should_receive(
         'replace_temporary_subdirectory_with_glob',
     ).with_args(
-        '/.borgmatic-snapshot-1234',
+        '/.borgmatic-snapshot',
         temporary_directory_prefix=module.BORGMATIC_SNAPSHOT_PREFIX,
     ).and_return('/.borgmatic-*')
 
     flexmock(module.glob).should_receive('glob').with_args('/.borgmatic-*').and_return(
-        ('/.borgmatic-snapshot-1234', '/.borgmatic-snapshot-5678'),
+        ('/.borgmatic-snapshot', '/.borgmatic-snapshot'),
     )
 
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/.borgmatic-snapshot-1234'
-    ).and_return(
-        True,
-    ).and_return(False)
-    flexmock(module.os.path).should_receive('isdir').with_args(
-        '/.borgmatic-snapshot-5678'
-    ).and_return(
-        True,
+    flexmock(module.os.path).should_receive('isdir').with_args('/.borgmatic-snapshot').and_return(
+        True
     ).and_return(False)
 
     flexmock(module).should_receive('delete_snapshot').with_args(
-        'btrfs', '/.borgmatic-snapshot-1234'
-    ).once()
-    flexmock(module).should_receive('delete_snapshot').with_args(
-        'btrfs', '/.borgmatic-snapshot-5678'
+        'btrfs', '/.borgmatic-snapshot'
     ).once()
 
     flexmock(module.os.path).should_receive('isdir').with_args('').and_return(False)
-
     flexmock(module.shutil).should_receive('rmtree').never()
 
     module.remove_data_source_dumps(