diff --git a/README.md b/README.md
index 29e11c544..4c1173f4b 100755
--- a/README.md
+++ b/README.md
@@ -208,6 +208,7 @@ Supported operating systems and hardware:
 * 2013-10-17, Created.<br/>
 
 ## History
+* v1.0, 2014-08-27, max connections is 32756, for st use mmap default. 0.9.209
 * v1.0, 2014-08-24, fix [#150](https://github.com/winlinvip/simple-rtmp-server/issues/150), forward should forward the sequence header when retry. 0.9.208.
 * v1.0, 2014-08-22, for [#165](https://github.com/winlinvip/simple-rtmp-server/issues/165), refine dh wrapper, ensure public key is 128bytes. 0.9.206.
 * v1.0, 2014-08-19, for [#160](https://github.com/winlinvip/simple-rtmp-server/issues/160), support forward/edge to flussonic, disable debug_srs_upnode to make flussonic happy. 0.9.201.
diff --git a/trunk/src/app/srs_app_server.cpp b/trunk/src/app/srs_app_server.cpp
index c52c0e18e..1f09fd192 100644
--- a/trunk/src/app/srs_app_server.cpp
+++ b/trunk/src/app/srs_app_server.cpp
@@ -545,8 +545,6 @@ int SrsServer::initialize_st()
     }
     srs_verbose("st_set_eventsys use linux epoll success");
     
-    // @remark, st alloc segment use mmap, which only support 32757 threads,
-    // if need to support more, for instance, 100k threads, define the macro MALLOC_STACK.
     if(st_init() != 0){
         ret = ERROR_ST_INITIALIZE;
         srs_error("st_init failed. ret=%d", ret);
@@ -554,6 +552,16 @@ int SrsServer::initialize_st()
     }
     srs_verbose("st_init success");
     
+    // @remark, st alloc segment use mmap, which only support 32757 threads,
+    // if need to support more, for instance, 100k threads, define the macro MALLOC_STACK.
+    if (_srs_config->get_max_connections() > 32756) {
+        ret = ERROR_ST_EXCEED_THREADS;
+        srs_error("st mmap for stack allocation must <= %d threads, "
+            "@see Makefile of st for MALLOC_STACK, please build st manually by "
+            "\"make EXTRA_CFLAGS=-DMALLOC_STACK linux-debug\", ret=%d", ret);
+        return ret;
+    }
+    
     // set current log id.
     _srs_context->generate_id();
     srs_trace("server main cid=%d", _srs_context->get_id());
diff --git a/trunk/src/core/srs_core.hpp b/trunk/src/core/srs_core.hpp
index 8ba58a250..8a7f6ba21 100644
--- a/trunk/src/core/srs_core.hpp
+++ b/trunk/src/core/srs_core.hpp
@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR "0"
 #define VERSION_MINOR "9"
-#define VERSION_REVISION "208"
+#define VERSION_REVISION "209"
 #define RTMP_SIG_SRS_VERSION VERSION_MAJOR"."VERSION_MINOR"."VERSION_REVISION
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
diff --git a/trunk/src/kernel/srs_kernel_error.hpp b/trunk/src/kernel/srs_kernel_error.hpp
index f071883db..27218bcac 100644
--- a/trunk/src/kernel/srs_kernel_error.hpp
+++ b/trunk/src/kernel/srs_kernel_error.hpp
@@ -87,6 +87,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #define ERROR_SYSTEM_CREATE_PIPE            1048
 #define ERROR_SYSTEM_FILE_SEEK              1049
 #define ERROR_SYSTEM_IO_INVALID             1050
+#define ERROR_ST_EXCEED_THREADS             1051
 
 ///////////////////////////////////////////////////////
 // RTMP protocol error.