diff --git a/src/http/ngx_http_upstream.h b/src/http/ngx_http_upstream.h
index d5246d117..315f85661 100644
--- a/src/http/ngx_http_upstream.h
+++ b/src/http/ngx_http_upstream.h
@@ -98,6 +98,7 @@ typedef struct {
     ngx_uint_t                       max_conns;
     ngx_uint_t                       max_fails;
     time_t                           fail_timeout;
+    ngx_msec_t                       slow_start;
 
     unsigned                         down:1;
     unsigned                         backup:1;
diff --git a/src/http/ngx_http_upstream_round_robin.h b/src/http/ngx_http_upstream_round_robin.h
index 634fe539e..d0f163197 100644
--- a/src/http/ngx_http_upstream_round_robin.h
+++ b/src/http/ngx_http_upstream_round_robin.h
@@ -35,6 +35,8 @@ struct ngx_http_upstream_rr_peer_s {
 
     ngx_uint_t                      max_fails;
     time_t                          fail_timeout;
+    ngx_msec_t                      slow_start;
+    ngx_msec_t                      start_time;
 
     ngx_uint_t                      down;          /* unsigned  down:1; */
 
diff --git a/src/stream/ngx_stream_upstream.h b/src/stream/ngx_stream_upstream.h
index 578ae0004..db2198417 100644
--- a/src/stream/ngx_stream_upstream.h
+++ b/src/stream/ngx_stream_upstream.h
@@ -54,6 +54,7 @@ typedef struct {
     ngx_uint_t                         max_conns;
     ngx_uint_t                         max_fails;
     time_t                             fail_timeout;
+    ngx_msec_t                         slow_start;
 
     unsigned                           down:1;
     unsigned                           backup:1;
diff --git a/src/stream/ngx_stream_upstream_round_robin.h b/src/stream/ngx_stream_upstream_round_robin.h
index 3a1bf36d6..8b5840809 100644
--- a/src/stream/ngx_stream_upstream_round_robin.h
+++ b/src/stream/ngx_stream_upstream_round_robin.h
@@ -35,6 +35,8 @@ struct ngx_stream_upstream_rr_peer_s {
 
     ngx_uint_t                       max_fails;
     time_t                           fail_timeout;
+    ngx_msec_t                       slow_start;
+    ngx_msec_t                       start_time;
 
     ngx_uint_t                       down;         /* unsigned  down:1; */