diff --git a/src/s3fs.cpp b/src/s3fs.cpp
index a9ae129..c8e92af 100644
--- a/src/s3fs.cpp
+++ b/src/s3fs.cpp
@@ -111,8 +111,6 @@ std::string bucket;
 std::string endpoint              = "us-east-1";
 std::string cipher_suites;
 std::string instance_name;
-s3fs_log_level debug_level        = S3FS_LOG_CRIT;
-const char*    s3fs_log_nest[S3FS_LOG_NEST_MAX] = {"", "  ", "    ", "      "};
 std::string aws_profile           = "default";
 
 //-------------------------------------------------------------------
@@ -160,10 +158,6 @@ static const std::string aws_secretkey         = "AWSSecretKey";
 //-------------------------------------------------------------------
 // Static functions : prototype
 //-------------------------------------------------------------------
-static void s3fs_usr2_handler(int sig);
-static bool set_s3fs_usr2_handler();
-static s3fs_log_level set_s3fs_log_level(s3fs_log_level level);
-static s3fs_log_level bumpup_s3fs_log_level();
 static bool is_special_name_folder_object(const char* path);
 static int chk_dir_object_type(const char* path, string& newpath, string& nowpath, string& nowcache, headers_t* pmeta = NULL, dirtype* pDirType = NULL);
 static int remove_old_type_dir(const string& path, dirtype type);
@@ -269,50 +263,6 @@ static int s3fs_removexattr(const char* path, const char* name);
 //-------------------------------------------------------------------
 // Functions
 //-------------------------------------------------------------------
-static void s3fs_usr2_handler(int sig)
-{
-  if(SIGUSR2 == sig){
-    bumpup_s3fs_log_level();
-  }
-}
-static bool set_s3fs_usr2_handler()
-{
-  struct sigaction sa;
-
-  memset(&sa, 0, sizeof(struct sigaction));
-  sa.sa_handler = s3fs_usr2_handler;
-  sa.sa_flags   = SA_RESTART;
-  if(0 != sigaction(SIGUSR2, &sa, NULL)){
-    return false;
-  }
-  return true;
-}
-
-static s3fs_log_level set_s3fs_log_level(s3fs_log_level level)
-{
-  if(level == debug_level){
-    return debug_level;
-  }
-  s3fs_log_level old = debug_level;
-  debug_level        = level;
-  setlogmask(LOG_UPTO(S3FS_LOG_LEVEL_TO_SYSLOG(debug_level)));
-  S3FS_PRN_CRIT("change debug level from %sto %s", S3FS_LOG_LEVEL_STRING(old), S3FS_LOG_LEVEL_STRING(debug_level));
-  return old;
-}
-
-static s3fs_log_level bumpup_s3fs_log_level()
-{
-  s3fs_log_level old = debug_level;
-  debug_level        = ( S3FS_LOG_CRIT == debug_level ? S3FS_LOG_ERR :
-                         S3FS_LOG_ERR  == debug_level ? S3FS_LOG_WARN :
-                         S3FS_LOG_WARN == debug_level ? S3FS_LOG_INFO :
-                         S3FS_LOG_INFO == debug_level ? S3FS_LOG_DBG :
-                         S3FS_LOG_CRIT );
-  setlogmask(LOG_UPTO(S3FS_LOG_LEVEL_TO_SYSLOG(debug_level)));
-  S3FS_PRN_CRIT("change debug level from %sto %s", S3FS_LOG_LEVEL_STRING(old), S3FS_LOG_LEVEL_STRING(debug_level));
-  return old;
-}
-
 static bool is_special_name_folder_object(const char* path)
 {
   if(!support_compat_dir){
@@ -5060,15 +5010,15 @@ static int my_fuse_opt_proc(void* data, const char* arg, int key, struct fuse_ar
     if(0 == STR2NCMP(arg, "dbglevel=")){
       const char* strlevel = strchr(arg, '=') + sizeof(char);
       if(0 == strcasecmp(strlevel, "silent") || 0 == strcasecmp(strlevel, "critical") || 0 == strcasecmp(strlevel, "crit")){
-        set_s3fs_log_level(S3FS_LOG_CRIT);
+        S3fsSignals::SetLogLevel(S3FS_LOG_CRIT);
       }else if(0 == strcasecmp(strlevel, "error") || 0 == strcasecmp(strlevel, "err")){
-        set_s3fs_log_level(S3FS_LOG_ERR);
+        S3fsSignals::SetLogLevel(S3FS_LOG_ERR);
       }else if(0 == strcasecmp(strlevel, "wan") || 0 == strcasecmp(strlevel, "warn") || 0 == strcasecmp(strlevel, "warning")){
-        set_s3fs_log_level(S3FS_LOG_WARN);
+        S3fsSignals::SetLogLevel(S3FS_LOG_WARN);
       }else if(0 == strcasecmp(strlevel, "inf") || 0 == strcasecmp(strlevel, "info") || 0 == strcasecmp(strlevel, "information")){
-        set_s3fs_log_level(S3FS_LOG_INFO);
+        S3fsSignals::SetLogLevel(S3FS_LOG_INFO);
       }else if(0 == strcasecmp(strlevel, "dbg") || 0 == strcasecmp(strlevel, "debug")){
-        set_s3fs_log_level(S3FS_LOG_DBG);
+        S3fsSignals::SetLogLevel(S3FS_LOG_DBG);
       }else{
         S3FS_PRN_EXIT("option dbglevel has unknown parameter(%s).", strlevel);
         return -1;
@@ -5082,7 +5032,7 @@ static int my_fuse_opt_proc(void* data, const char* arg, int key, struct fuse_ar
     //
     if(0 == strcmp(arg, "-d") || 0 == strcmp(arg, "--debug")){
       if(!IS_S3FS_LOG_INFO() && !IS_S3FS_LOG_DBG()){
-        set_s3fs_log_level(S3FS_LOG_INFO);
+        S3fsSignals::SetLogLevel(S3FS_LOG_INFO);
         return 0;
       }
       if(0 == strcmp(arg, "--debug")){
@@ -5094,7 +5044,7 @@ static int my_fuse_opt_proc(void* data, const char* arg, int key, struct fuse_ar
     // "f2" is not used no more.
     // (set S3FS_LOG_DBG)
     if(0 == strcmp(arg, "f2")){
-      set_s3fs_log_level(S3FS_LOG_DBG);
+      S3fsSignals::SetLogLevel(S3FS_LOG_DBG);
       return 0;
     }
     if(0 == strcmp(arg, "curldbg")){
@@ -5184,7 +5134,7 @@ int main(int argc, char* argv[])
 
   // init syslog(default CRIT)
   openlog("s3fs", LOG_PID | LOG_ODELAY | LOG_NOWAIT, LOG_USER);
-  set_s3fs_log_level(debug_level);
+  S3fsSignals::SetLogLevel(debug_level);
 
   // init xml2
   xmlInitParser();
@@ -5511,14 +5461,6 @@ int main(int argc, char* argv[])
     s3fs_oper.removexattr = s3fs_removexattr;
   }
 
-  // set signal handler for debugging
-  if(!set_s3fs_usr2_handler()){
-    S3FS_PRN_EXIT("could not set signal handler for SIGUSR2.");
-    S3fsCurl::DestroyS3fsCurl();
-    s3fs_destroy_global_ssl();
-    exit(EXIT_FAILURE);
-  }
-
   // now passing things off to fuse, fuse will finish evaluating the command line args
   fuse_res = fuse_main(custom_args.argc, custom_args.argv, &s3fs_oper, NULL);
   fuse_opt_free_args(&custom_args);
diff --git a/src/sighandlers.cpp b/src/sighandlers.cpp
index 4da7f58..a1edc82 100644
--- a/src/sighandlers.cpp
+++ b/src/sighandlers.cpp
@@ -41,6 +41,12 @@
 
 using namespace std;
 
+//-------------------------------------------------------------------
+// Global variables
+//-------------------------------------------------------------------
+s3fs_log_level debug_level        = S3FS_LOG_CRIT;
+const char*    s3fs_log_nest[S3FS_LOG_NEST_MAX] = {"", "  ", "    ", "      "};
+
 //-------------------------------------------------------------------
 // Class S3fsSignals
 //-------------------------------------------------------------------
@@ -129,6 +135,53 @@ void* S3fsSignals::CheckCacheWorker(void* arg)
   return NULL;
 }
 
+void S3fsSignals::HandlerUSR2(int sig)
+{
+  if(SIGUSR2 == sig){
+    S3fsSignals::BumpupLogLevel();
+  }else{
+    S3FS_PRN_ERR("The handler for SIGUSR2 received signal(%d)", sig);
+  }
+}
+
+bool S3fsSignals::InitUsr2Handler()
+{
+  struct sigaction sa;
+
+  memset(&sa, 0, sizeof(struct sigaction));
+  sa.sa_handler = S3fsSignals::HandlerUSR2;
+  sa.sa_flags   = SA_RESTART;
+  if(0 != sigaction(SIGUSR2, &sa, NULL)){
+    return false;
+  }
+  return true;
+}
+
+s3fs_log_level S3fsSignals::SetLogLevel(s3fs_log_level level)
+{
+  if(level == debug_level){
+    return debug_level;
+  }
+  s3fs_log_level old = debug_level;
+  debug_level        = level;
+  setlogmask(LOG_UPTO(S3FS_LOG_LEVEL_TO_SYSLOG(debug_level)));
+  S3FS_PRN_CRIT("change debug level from %sto %s", S3FS_LOG_LEVEL_STRING(old), S3FS_LOG_LEVEL_STRING(debug_level));
+  return old;
+}
+
+s3fs_log_level S3fsSignals::BumpupLogLevel()
+{
+  s3fs_log_level old = debug_level;
+  debug_level        = ( S3FS_LOG_CRIT == debug_level ? S3FS_LOG_ERR :
+                         S3FS_LOG_ERR  == debug_level ? S3FS_LOG_WARN :
+                         S3FS_LOG_WARN == debug_level ? S3FS_LOG_INFO :
+                         S3FS_LOG_INFO == debug_level ? S3FS_LOG_DBG :
+                         S3FS_LOG_CRIT );
+  setlogmask(LOG_UPTO(S3FS_LOG_LEVEL_TO_SYSLOG(debug_level)));
+  S3FS_PRN_CRIT("change debug level from %sto %s", S3FS_LOG_LEVEL_STRING(old), S3FS_LOG_LEVEL_STRING(debug_level));
+  return old;
+}
+
 //-------------------------------------------------------------------
 // Methods
 //-------------------------------------------------------------------
@@ -139,6 +192,9 @@ S3fsSignals::S3fsSignals() : pThreadUsr1(NULL), pSemUsr1(NULL)
       S3FS_PRN_ERR("failed creating thread for SIGUSR1 handler, but continue...");
     }
   }
+  if(!S3fsSignals::InitUsr2Handler()){
+    S3FS_PRN_ERR("failed to initialize SIGUSR2 handler for bumping log level, but continue...");
+  }
 }
 
 S3fsSignals::~S3fsSignals()
diff --git a/src/sighandlers.h b/src/sighandlers.h
index 25bdae3..0bebcef 100644
--- a/src/sighandlers.h
+++ b/src/sighandlers.h
@@ -41,6 +41,9 @@ class S3fsSignals
     static void HandlerUSR1(int sig);
     static void* CheckCacheWorker(void* arg);
 
+    static void HandlerUSR2(int sig);
+    static bool InitUsr2Handler(void);
+
     S3fsSignals();
     ~S3fsSignals();
 
@@ -53,6 +56,9 @@ class S3fsSignals
     static bool Destroy(void);
 
     static bool SetUsr1Handler(const char* path);
+
+    static s3fs_log_level SetLogLevel(s3fs_log_level level);
+    static s3fs_log_level BumpupLogLevel(void);
 };
 
 #endif // S3FS_SIGHANDLERS_H_