diff --git a/cpukit/libfs/src/dosfs/dosfs.h b/cpukit/libfs/src/dosfs/dosfs.h
index 211fc2d3f2..ea650b2f7e 100644
--- a/cpukit/libfs/src/dosfs/dosfs.h
+++ b/cpukit/libfs/src/dosfs/dosfs.h
@@ -25,6 +25,13 @@
 extern "C" {
 #endif
 
+/**
+ * @brief Semaphore count per FAT filesystem instance.
+ *
+ * This can be used for system configuration via <rtems/confdefs.h>.
+ */
+#define RTEMS_DOSFS_SEMAPHORES_PER_INSTANCE 1
+
 int rtems_dosfs_initialize(rtems_filesystem_mount_table_entry_t *mt_entry,
                            const void                           *data);
 
diff --git a/testsuites/fstests/mdosfs_support/fs_support.c b/testsuites/fstests/mdosfs_support/fs_support.c
index 27882b8216..03c377e03e 100644
--- a/testsuites/fstests/mdosfs_support/fs_support.c
+++ b/testsuites/fstests/mdosfs_support/fs_support.c
@@ -82,6 +82,7 @@ void test_shutdown_filesystem(void)
  */
 #define CONFIGURE_RTEMS_INIT_TASKS_TABLE
 
+#define CONFIGURE_MAXIMUM_SEMAPHORES RTEMS_DOSFS_SEMAPHORES_PER_INSTANCE
 #define CONFIGURE_MAXIMUM_TASKS                     10
 #define CONFIGURE_USE_IMFS_AS_BASE_FILESYSTEM
 #define CONFIGURE_MAXIMUM_DRIVERS                   10