diff --git a/src/os/unix/ngx_readv_chain.c b/src/os/unix/ngx_readv_chain.c
index 8836c817d..e4eb5ff32 100644
--- a/src/os/unix/ngx_readv_chain.c
+++ b/src/os/unix/ngx_readv_chain.c
@@ -10,7 +10,11 @@
 #include <ngx_event.h>
 
 
-#define NGX_IOVS  16
+#if (IOV_MAX > 64)
+#define NGX_IOVS  64
+#else
+#define NGX_IOVS  IOV_MAX
+#endif
 
 
 #if (NGX_HAVE_KQUEUE)