docs: A few notes

Author: igorlukanin

docs/pages/product/caching/running-in-production.mdx

@@ -325,6 +325,28 @@ Refresh worker should be able to finish pre-aggregation refresh before
 garbage collection starts. It means that all pre-aggregation partitions
 should be built before any tables are removed.
 
+#### Supported file systems
+
+The garbage collection mechanism relies on the ability of the underlying file
+system to report the creation time of a file.
+
+If the file system does not support getting the creation time, you will see the
+following error message in Cube Store logs:
+
+```
+ERROR [cubestore::remotefs::cleanup] <pid:1>
+error while getting created time for file "<name>.chunk.parquet":
+creation time is not available for the filesystem
+```
+
+<ReferenceBox>
+
+XFS is known to not support getting the creation time of a file.
+Please see [this issue](https://github.com/cube-js/cube/issues/7905#issuecomment-2504212623)
+for possible workarounds.
+
+</ReferenceBox>
+
 ## Security
 
 ### Authentication

docs/pages/reference/data-model/pre-aggregations.mdx

@@ -1635,6 +1635,13 @@ cubes:
 
 </CodeTabs>
 
+<ReferenceBox>
+
+In some cases, indexes would not work with `original_sql` pre-aggregations.
+Please [track this issue](https://github.com/cube-js/cube/issues/7420).
+
+</ReferenceBox>
+
 #### `type`
 
 This option is used to define [aggregating indexes][ref-aggregating-indexes]