Getting Started: Update faq.md

photoprism/photoprism#3856 (comment)

docs/getting-started/faq.md

@@ -328,6 +328,14 @@ The [smallest configurable size](../user-guide/settings/advanced.md#dynamic-and-
     Reducing the *Static Size Limit* of thumbnails has a **significant impact on [face recognition](../user-guide/organize/people.md)
     and image classification** results. Simply put, it means that the indexer can no longer see properly.
 
+### Why is my configured memory limit exceeded when indexing, even though PhotoPrism doesn't actually seem to use that much memory?
+
+When [indexing a media library](../user-guide/library/originals.md), many files are opened and processed very quickly, which is not a typical workload compared to other containerized applications and services. Various libraries and external applications simultaneously interact with each other in complex ways, so single spikes are inevitable. Some memory is also used by the kernel for buffered I/O to improve performance, although the extent to which caching counts towards a limit may vary.
+
+We therefore recommend not to set hard memory limits, unless you are familiar with memory management and understand the implications. Instead, you should [reduce the number of indexing workers](https://docs.photoprism.app/getting-started/config-options/#index-workers) and [limit file size and resolution](config-options.md#storage) if you are low on resources or want to limit memory usage for other reasons.
+
+[View System Requirements ›](index.md#system-requirements){ class="pr-3 block-xs" } [Get Performance Tips ›](troubleshooting/performance.md#troubleshooting)
+
 ### When should I perform a complete rescan?
 
 We recommend performing a [complete rescan](../user-guide/library/originals.md#when-should-complete-rescan-be-selected) after major updates to take advantage of new search filters and sorting options. Be sure to [read the notes for each release](../release-notes.md) to see what changes have been made and if they might affect your library, for example, because of the file types you have or because new search features have been added. If you encounter problems that you cannot solve otherwise (i.e. before reporting a bug), please also try a rescan and see if it solves the problem.