Index: head/sys/conf/NOTES
===================================================================
--- head/sys/conf/NOTES
+++ head/sys/conf/NOTES
@@ -578,6 +578,17 @@
 #
 options 	STACK
 
+#
+# The NUM_CORE_FILES option specifies the limit for the number of core
+# files generated by a particular process, when the core file format
+# specifier includes the %I pattern. Since we only have 1 character for
+# the core count in the format string, meaning the range will be 0-9, the
+# maximum value allowed for this option is 10.
+# This core file limit can be adjusted at runtime via the debug.ncores
+# sysctl.
+#
+options 	NUM_CORE_FILES=5
+
 
 #####################################################################
 # PERFORMANCE MONITORING OPTIONS
Index: head/sys/conf/options
===================================================================
--- head/sys/conf/options
+++ head/sys/conf/options
@@ -65,6 +65,7 @@
 EARLY_PRINTF	opt_global.h
 TEXTDUMP_PREFERRED	opt_ddb.h
 TEXTDUMP_VERBOSE	opt_ddb.h
+NUM_CORE_FILES	opt_global.h
 
 # Miscellaneous options.
 ADAPTIVE_LOCKMGRS
Index: head/sys/kern/kern_sig.c
===================================================================
--- head/sys/kern/kern_sig.c
+++ head/sys/kern/kern_sig.c
@@ -3142,8 +3142,12 @@
  * We only have 1 character for the core count in the format
  * string, so the range will be 0-9
  */
-#define MAX_NUM_CORES 10
-static int num_cores = 5;
+#define	MAX_NUM_CORE_FILES 10
+#ifndef NUM_CORE_FILES
+#define	NUM_CORE_FILES 5
+#endif
+CTASSERT(NUM_CORE_FILES >= 0 && NUM_CORE_FILES <= MAX_NUM_CORE_FILES);
+static int num_cores = NUM_CORE_FILES;
 
 static int
 sysctl_debug_num_cores_check (SYSCTL_HANDLER_ARGS)
@@ -3155,8 +3159,8 @@
 	error = sysctl_handle_int(oidp, &new_val, 0, req);
 	if (error != 0 || req->newptr == NULL)
 		return (error);
-	if (new_val > MAX_NUM_CORES)
-		new_val = MAX_NUM_CORES;
+	if (new_val > MAX_NUM_CORE_FILES)
+		new_val = MAX_NUM_CORE_FILES;
 	if (new_val < 0)
 		new_val = 0;
 	num_cores = new_val;