diff --git a/runbot_builder/tools.py b/runbot_builder/tools.py
index 31a8a225..cc0e42dd 100644
--- a/runbot_builder/tools.py
+++ b/runbot_builder/tools.py
@@ -26,7 +26,6 @@ class RunbotClient():
         self.host = None
         self.count = 0
         self.max_count = 60
-        self.next_git_gc_date = datetime.now() + timedelta(minutes=random.randint(5, 15))
 
     def on_start(self):
         pass
@@ -38,6 +37,7 @@ class RunbotClient():
         signal.signal(signal.SIGTERM, self.signal_handler)
         signal.signal(signal.SIGQUIT, self.dump_stack)
         self.host = self.env['runbot.host']._get_current()
+        self.update_next_git_gc_date()
         self.host._bootstrap()
         logging.info(
             'Host %s running with %s slots on pid %s%s',
@@ -83,13 +83,21 @@ class RunbotClient():
     def sleep(self, t):
         self.ask_interrupt.wait(t)
 
+    def update_next_git_gc_date(self):
+        now = datetime.now()
+        gc_hour = int(self.env['ir.config_parameter'].sudo().get_param('runbot.git_gc_hour', '23'))
+        gc_minutes = self.host.id % 60  # deterministic minutes
+        self.next_git_gc_date = datetime(now.year, now.month, now.day, gc_hour, gc_minutes)
+        while self.next_git_gc_date <= now:
+            self.next_git_gc_date += timedelta(days=1)
+        _logger.info('Next git gc scheduled on %s', self.next_git_gc_date)
+
     def git_gc(self):
         """ git gc once a day """
-        if datetime.now() > self.next_git_gc_date:
+        if self.next_git_gc_date < datetime.now():
             _logger.info('Starting git gc on repositories')
             self.env['runbot.runbot']._git_gc(self.host)
-            self.next_git_gc_date = datetime.now() + timedelta(hours=2, minutes=random.randint(0, 59))
-            _logger.info('Next git gc scheduled on %s', self.next_git_gc_date)
+            self.update_next_git_gc_date()
 
 def run(client_class):
     # parse args
@@ -135,5 +143,9 @@ def run(client_class):
             env = odoo.api.Environment(cr, odoo.SUPERUSER_ID, {})
             client = client_class(env)
             # run main loop
-            client.main_loop()
+            try:
+                client.main_loop()
+            except Exception as e:
+                _logger.exception(str(e))
+                raise e
     _logger.info("Stopping gracefully")