diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 8999eee5f14..d94d0333aad 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -8145,7 +8145,8 @@ dynamic_library_path = 'C:\tools\postgresql;H:\my_project\lib;$libdir'
        <para>
         When set to false, which is the default, <productname>PostgreSQL</productname>
         will raise a PANIC-level error on failure to flush modified data files
-        to the filesystem.  This causes the database server to crash.
+        to the filesystem.  This causes the database server to crash.  This
+        parameter can only be set at server start.
        </para>
        <para>
         On some operating systems, the status of data in the kernel's page
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 1404946c410..6f7fa22c6c1 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -665,7 +665,9 @@
 
 #exit_on_error = off			# terminate session on any error?
 #restart_after_crash = on		# reinitialize after backend crash?
-#data_sync_retry = off			# retry or panic on failure to fsync data?
+#data_sync_retry = off			# retry or panic on failure to fsync
+					# data?
+					# (change requires restart)
 
 
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