diff --git a/docs/topics/broad-crawls.rst b/docs/topics/broad-crawls.rst
index cace1f883..e99b0932a 100644
--- a/docs/topics/broad-crawls.rst
+++ b/docs/topics/broad-crawls.rst
@@ -68,6 +68,10 @@ should pick a concurrency where CPU usage is at 80-90%.
 Increasing concurrency also increases memory usage. If memory usage is a
 concern, you might need to lower your global concurrency limit accordingly.
 
+While performing a broad crawl with a high :setting:`CONCURRENT_REQUESTS` value,
+you may encounter OS specific errors regarding the number of currently open files.
+Some systems allow this limit to be increased or removed. If you cannot do so,
+you will need to reduce the :setting:`CONCURRENT_REQUESTS` value.
 
 Increase Twisted IO thread pool maximum size
 ============================================