diff --git a/.gitignore b/.gitignore
index 5d4619d10..7677a0718 100644
--- a/.gitignore
+++ b/.gitignore
@@ -86,3 +86,4 @@ venv
 gns3server/agent/gns3_copilot/cache/tiktoken/
 
 gns3.log
+/configs/
diff --git a/gns3server/controller/project.py b/gns3server/controller/project.py
index 12897eae3..c525473e0 100644
--- a/gns3server/controller/project.py
+++ b/gns3server/controller/project.py
@@ -1158,23 +1158,25 @@ class Project:
             # data_link_type decides which links host an inherited copy (serial
             # links are skipped unless a WAN encapsulation is chosen), so a change
             # needs a full re-fan-out: drop every copy, then re-apply.
-            await self._marker_apply_concurrently(
-                affected,
-                lambda link: link.stop_marker(f"global-{name}", inherited=True, dump=False),
-                lambda link, e: f"Failed to remove inherited marker global-{name} from link {link.id}: {e}",
-            )
+            for link in affected:
+                try:
+                    await link.stop_marker(f"global-{name}", inherited=True, dump=False, memory_only=True)
+                except ControllerError as e:
+                    log.warning("Failed to remove inherited marker global-%s from link %s: %s", name, link.id, e)
             await self._apply_def_to_all_links(name)
         else:
-            # Sync: update every inherited copy across all links.
-            await self._marker_apply_concurrently(
-                affected,
-                lambda link: link.update_marker(
-                    f"global-{name}", bpf=d["bpf"], tag=d.get("tag"), direction=d.get("direction"),
-                    color=d.get("color"), highlight_duration=d.get("highlight_duration"), inherited=True,
-                    dump=False
-                ),
-                lambda link, e: f"Failed to sync marker global-{name} on link {link.id}: {e}",
-            )
+            # Sync: update every inherited copy across all links in memory, then
+            # batch-push to computes (one PUT /nios/batch per compute).
+            for link in affected:
+                try:
+                    await link.update_marker(
+                        f"global-{name}", bpf=d["bpf"], tag=d.get("tag"), direction=d.get("direction"),
+                        color=d.get("color"), highlight_duration=d.get("highlight_duration"), inherited=True,
+                        dump=False, memory_only=True
+                    )
+                except ControllerError as e:
+                    log.warning("Failed to sync marker global-%s on link %s: %s", name, link.id, e)
+            await self._batch_update_link_nios(affected)
         self.dump()
         self.emit_notification("project.updated", self.asdict())
 
@@ -1195,12 +1197,13 @@ class Project:
             if f"global-{name}" in link.markers
             and link.markers[f"global-{name}"].get("inherited_from") == name
         ]
-        await self._marker_apply_concurrently(
-            affected,
-            lambda link: link.stop_marker(f"global-{name}", inherited=True),
-            # A missing compute or broken link shouldn't block the delete.
-            lambda link, e: f"Failed to remove inherited marker global-{name} from link {link.id}: {e}",
-        )
+        for link in affected:
+            try:
+                await link.stop_marker(f"global-{name}", inherited=True, memory_only=True)
+            except ControllerError as e:
+                # A missing compute or broken link shouldn't block the delete.
+                log.warning("Failed to remove inherited marker global-%s from link %s: %s", name, link.id, e)
+        await self._batch_update_link_nios(affected)
 
         self.dump()
         self.emit_notification("project.updated", self.asdict())
diff --git a/gns3server/controller/udp_link.py b/gns3server/controller/udp_link.py
index 4b0bec4ec..86f863010 100644
--- a/gns3server/controller/udp_link.py
+++ b/gns3server/controller/udp_link.py
@@ -497,7 +497,7 @@ class UDPLink(Link):
         self._link_data[1]["markers"] = node2_markers
         self._link_data[1]["suspend"] = self._suspended
 
-    async def stop_marker(self, name, inherited=False, dump=True):
+    async def stop_marker(self, name, inherited=False, dump=True, memory_only=False):
         """
         Remove a traffic-insight marker from this link.
 
@@ -522,6 +522,12 @@ class UDPLink(Link):
 
         capture_node_id = self._markers[name].get("capture_node_id")
         del self._markers[name]
+        if memory_only:
+            # Project-level def-delete fan-out: marker is gone from _markers;
+            # refresh _link_data so the batch dispatch drops it from uBridge
+            # via full reapply. No per-link delete round-trip, notification or dump.
+            self._refresh_link_data()
+            return
         # Remove the marker filter + its pcap on the capture node directly — NOT a
         # full NIO reapply (which would reset_packet_filters and close/reopen every
         # sibling marker's pcap). delete_packet_filter removes just this filter;
@@ -541,7 +547,7 @@ class UDPLink(Link):
         if dump:
             self._project.dump()
 
-    async def update_marker(self, name, bpf=None, tag=None, enabled=None, direction=_UNSET, color=None, highlight_duration=None, inherited=False, dump=True):
+    async def update_marker(self, name, bpf=None, tag=None, enabled=None, direction=_UNSET, color=None, highlight_duration=None, inherited=False, dump=True, memory_only=False):
         """
         Update an existing marker's fields and push to uBridge fine-grained — no
         full NIO reapply, so sibling markers' pcaps stay open. bpf/tag/direction
@@ -590,6 +596,13 @@ class UDPLink(Link):
         if direction is not _UNSET:
             marker_info["direction"] = direction  # None = clear back to both directions
 
+        if memory_only:
+            # Project-level def sync fan-out: state is already merged into
+            # _markers; just refresh _link_data so the batch dispatch carries
+            # it. No per-link uBridge rebuild, notification or dump.
+            self._refresh_link_data()
+            return
+
         # Push to uBridge fine-grained — NO full NIO reapply (which would
         # reset_packet_filters and close/reopen every sibling marker's pcap):
         #   * bpf/tag/direction changed → rebuild just this filter (delete + add),