diff --git a/src/elements/core.c b/src/elements/core.c
index 9142cf32..ef606fc5 100644
--- a/src/elements/core.c
+++ b/src/elements/core.c
@@ -8047,7 +8047,7 @@ static int __cold mdbx_setup_dxb(MDBX_env *env, const int lck_rc) {
   }
 
   err = mdbx_mmap(env->me_flags, &env->me_dxb_mmap, env->me_dbgeo.now,
-                  env->me_dbgeo.upper, lck_rc);
+                  env->me_dbgeo.upper, lck_rc ? MMAP_OPTION_TRUNCATE : 0);
   if (unlikely(err != MDBX_SUCCESS))
     return err;
 
@@ -8379,7 +8379,8 @@ static int __cold mdbx_setup_lck(MDBX_env *env, char *lck_pathname,
   env->me_maxreaders = (unsigned)maxreaders;
 
   err = mdbx_mmap(MDBX_WRITEMAP, &env->me_lck_mmap, (size_t)size, (size_t)size,
-                  lck_seize_rc);
+                  lck_seize_rc ? MMAP_OPTION_TRUNCATE | MMAP_OPTION_SEMAPHORE
+                               : MMAP_OPTION_SEMAPHORE);
   if (unlikely(err != MDBX_SUCCESS))
     goto bailout;
 
diff --git a/src/elements/osal.c b/src/elements/osal.c
index 797ecef3..c1014c6a 100644
--- a/src/elements/osal.c
+++ b/src/elements/osal.c
@@ -1166,7 +1166,7 @@ static int mdbx_check_fs_local(mdbx_filehandle_t handle, int flags) {
 
 MDBX_INTERNAL_FUNC int mdbx_mmap(const int flags, mdbx_mmap_t *map,
                                  const size_t size, const size_t limit,
-                                 const bool truncate) {
+                                 const unsigned options) {
   assert(size <= limit);
   map->limit = 0;
   map->current = 0;
@@ -1180,7 +1180,7 @@ MDBX_INTERNAL_FUNC int mdbx_mmap(const int flags, mdbx_mmap_t *map,
   if (unlikely(err != MDBX_SUCCESS))
     return err;
 
-  if ((flags & MDBX_RDONLY) == 0 && truncate) {
+  if ((flags & MDBX_RDONLY) == 0 && (options & MMAP_OPTION_TRUNCATE) != 0) {
     err = mdbx_ftruncate(map->fd, size);
     if (err != MDBX_SUCCESS)
       return err;
@@ -1243,7 +1243,18 @@ MDBX_INTERNAL_FUNC int mdbx_mmap(const int flags, mdbx_mmap_t *map,
 
   map->address = mmap(
       NULL, limit, (flags & MDBX_WRITEMAP) ? PROT_READ | PROT_WRITE : PROT_READ,
-      MAP_SHARED, map->fd, 0);
+      MAP_SHARED | MAP_FILE
+#ifdef MAP_NOSYNC
+          | (((options & MMAP_OPTION_SEMAPHORE) != 0 ||
+              F_ISSET(flags, MDBX_UTTERLY_NOSYNC))
+                 ? MAP_NOSYNC
+                 : 0)
+#endif
+#ifdef MAP_HASSEMAPHORE
+          | ((options & MMAP_OPTION_SEMAPHORE) ? MAP_HASSEMAPHORE : 0)
+#endif
+          ,
+      map->fd, 0);
 
   if (unlikely(map->address == MAP_FAILED)) {
     map->limit = 0;
diff --git a/src/elements/osal.h b/src/elements/osal.h
index 04af577d..957d2d8a 100644
--- a/src/elements/osal.h
+++ b/src/elements/osal.h
@@ -649,9 +649,11 @@ typedef struct mdbx_mmap_param {
 #endif
 } mdbx_mmap_t;
 
+#define MMAP_OPTION_TRUNCATE 1
+#define MMAP_OPTION_SEMAPHORE 2
 MDBX_INTERNAL_FUNC int mdbx_mmap(const int flags, mdbx_mmap_t *map,
                                  const size_t must, const size_t limit,
-                                 const bool truncate);
+                                 const unsigned options);
 MDBX_INTERNAL_FUNC int mdbx_munmap(mdbx_mmap_t *map);
 MDBX_INTERNAL_FUNC int mdbx_mresize(int flags, mdbx_mmap_t *map, size_t current,
                                     size_t wanna);