diff --git a/doc/configuration.txt b/doc/configuration.txt
index d10c68972..90e738d2f 100644
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1871,6 +1871,7 @@ The following keywords are supported in the "global" section :
    - tune.bufsize
    - tune.bufsize.small
    - tune.comp.maxlevel
+   - tune.defaults.purge
    - tune.disable-fast-forward
    - tune.disable-zero-copy-forwarding
    - tune.epoll.mask-events
@@ -4121,6 +4122,19 @@ tune.comp.maxlevel <number>
   Each stream using compression initializes the compression algorithm with
   this value. The default value is 1.
 
+tune.defaults.purge
+  For dynamic backends support, all named defaults sections are now kept in
+  memory after parsing. This is necessary as backend added at runtime must be
+  based on a named defaults for its configuration.
+
+  This may consume significant memory if the number of defaults instances is
+  important. In this case and if dynamic backend feature is unnecessary, it's
+  possible to use this option to force deletion of defaults section after
+  parsing. It is still mandatory though to keep referenced defaults section
+  which contain settings whose cannot be copied by their referencing proxies.
+  For example, this is the case if the defaults section defines TCP/HTTP rules
+  or a tcpcheck ruleset.
+
 tune.disable-fast-forward
   Disables the data fast-forwarding. It is a mechanism to optimize the data
   forwarding by passing data directly from a side to the other one without
diff --git a/include/haproxy/global-t.h b/include/haproxy/global-t.h
index c8e6dd82d..6b1f3e7b6 100644
--- a/include/haproxy/global-t.h
+++ b/include/haproxy/global-t.h
@@ -67,7 +67,7 @@
 #define GTUNE_USE_SYSTEMD        (1<<10)
 
 #define GTUNE_BUSY_POLLING       (1<<11)
-/* (1<<12) unused */
+#define GTUNE_PURGE_DEFAULTS     (1<<12)
 #define GTUNE_SET_DUMPABLE       (1<<13)
 #define GTUNE_USE_EVPORTS        (1<<14)
 #define GTUNE_STRICT_LIMITS      (1<<15)
diff --git a/include/haproxy/proxy.h b/include/haproxy/proxy.h
index ad6f6905b..ed86925d2 100644
--- a/include/haproxy/proxy.h
+++ b/include/haproxy/proxy.h
@@ -72,6 +72,8 @@ void init_new_proxy(struct proxy *p);
 void defaults_px_destroy(struct proxy *px);
 void defaults_px_destroy_all_unref(void);
 void defaults_px_detach(struct proxy *px);
+void defaults_px_ref_all(void);
+void defaults_px_unref_all(void);
 
 void proxy_ref_defaults(struct proxy *px, struct proxy *defpx);
 void proxy_unref_defaults(struct proxy *px);
diff --git a/src/cfgparse-global.c b/src/cfgparse-global.c
index 2317cc5dd..aafca44ea 100644
--- a/src/cfgparse-global.c
+++ b/src/cfgparse-global.c
@@ -1423,6 +1423,9 @@ static int cfg_parse_global_tune_opts(char **args, int section_type,
 
 		return 0;
 	}
+	else if (strcmp(args[0], "tune.defaults.purge") == 0) {
+		global.tune.options |= GTUNE_PURGE_DEFAULTS;
+	}
 	else if (strcmp(args[0], "tune.pattern.cache-size") == 0) {
 		if (*(args[1]) == 0) {
 			memprintf(err, "'%s' expects a positive numeric value", args[0]);
@@ -1869,6 +1872,7 @@ static struct cfg_kw_list cfg_kws = {ILH, {
 	{ CFG_GLOBAL, "tune.bufsize", cfg_parse_global_tune_opts },
 	{ CFG_GLOBAL, "tune.chksize", cfg_parse_global_unsupported_opts },
 	{ CFG_GLOBAL, "tune.comp.maxlevel", cfg_parse_global_tune_opts },
+	{ CFG_GLOBAL, "tune.defaults.purge", cfg_parse_global_tune_opts },
 	{ CFG_GLOBAL, "tune.disable-fast-forward", cfg_parse_global_tune_forward_opts },
 	{ CFG_GLOBAL, "tune.disable-zero-copy-forwarding", cfg_parse_global_tune_forward_opts },
 	{ CFG_GLOBAL, "tune.glitches.kill.cpu-usage", cfg_parse_global_tune_opts },
diff --git a/src/haproxy.c b/src/haproxy.c
index 929a86537..c4a755f5e 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -2105,8 +2105,13 @@ static void step_init_2(int argc, char** argv)
 	}
 	last_defproxy = NULL; /* This variable is not used after parsing. */
 
-	/* destroy unreferenced defaults proxies  */
-	defaults_px_destroy_all_unref();
+	if (global.tune.options & GTUNE_PURGE_DEFAULTS) {
+		/* destroy unreferenced defaults proxies  */
+		defaults_px_destroy_all_unref();
+	}
+	else {
+		defaults_px_ref_all();
+	}
 
 	list_for_each_entry(prcf, &pre_check_list, list) {
 		err_code |= prcf->fct();
@@ -2749,6 +2754,9 @@ void deinit(void)
 	 * they are respectively cleaned up in sink_deinit() and deinit_log_forward()
 	 */
 
+	/* If named defaults were preserved, ensure refcount is resetted. */
+	if (!(global.tune.options & GTUNE_PURGE_DEFAULTS))
+		defaults_px_unref_all();
 	/* All proxies are removed now, so every defaults should also be freed
 	 * when their refcount reached zero.
 	 */
diff --git a/src/proxy.c b/src/proxy.c
index d828ded9c..41cb8042d 100644
--- a/src/proxy.c
+++ b/src/proxy.c
@@ -1667,6 +1667,30 @@ void defaults_px_detach(struct proxy *px)
 	/* If not destroyed, <px> can still be accessed in <defaults_list>. */
 }
 
+void defaults_px_ref_all(void)
+{
+	struct proxy *px;
+
+	for (px = cebis_item_first(&defproxy_by_name, conf.name_node, id, struct proxy);
+	     px;
+	     px = cebis_item_next(&defproxy_by_name, conf.name_node, id, px)) {
+		++px->conf.refcount;
+	}
+}
+
+void defaults_px_unref_all(void)
+{
+	struct proxy *px, *nx;
+
+	for (px = cebis_item_first(&defproxy_by_name, conf.name_node, id, struct proxy); px; px = nx) {
+		nx = cebis_item_next(&defproxy_by_name, conf.name_node, id, px);
+
+		BUG_ON(!px->conf.refcount);
+		if (!--px->conf.refcount)
+			defaults_px_destroy(px);
+	}
+}
+
 /* Add a reference on the default proxy <defpx> for the proxy <px> Nothing is
  * done if <px> already references <defpx>. Otherwise, the default proxy
  * refcount is incremented by one. For now, this operation is not thread safe