diff --git a/server/src/com/cloud/alert/AlertManagerImpl.java b/server/src/com/cloud/alert/AlertManagerImpl.java
index 4f58ef415b5..0368e27b709 100755
--- a/server/src/com/cloud/alert/AlertManagerImpl.java
+++ b/server/src/com/cloud/alert/AlertManagerImpl.java
@@ -289,7 +289,7 @@ public class AlertManagerImpl implements AlertManager {
         	
 	        // Calculate CPU and RAM capacities
 	        // 	get all hosts...even if they are not in 'UP' state
-	        List<HostVO> hosts = _resourceMgr.listAllHostsInAllZonesByType(Host.Type.Routing);
+	        List<HostVO> hosts = _resourceMgr.listAllNotInMaintenanceHostsInOneZone(Host.Type.Routing, null);	        	        
 	        for (HostVO host : hosts) {
 	        	_capacityMgr.updateCapacityForHost(host);
 	        }
diff --git a/server/src/com/cloud/capacity/CapacityManagerImpl.java b/server/src/com/cloud/capacity/CapacityManagerImpl.java
index 24465df0278..f13503c7ce7 100755
--- a/server/src/com/cloud/capacity/CapacityManagerImpl.java
+++ b/server/src/com/cloud/capacity/CapacityManagerImpl.java
@@ -17,6 +17,7 @@
  */
 package com.cloud.capacity;
 
+import java.net.URI;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
@@ -44,7 +45,9 @@ import com.cloud.host.HostVO;
 import com.cloud.host.Status;
 import com.cloud.host.dao.HostDao;
 import com.cloud.offering.ServiceOffering;
+import com.cloud.resource.ResourceListener;
 import com.cloud.resource.ResourceManager;
+import com.cloud.resource.ServerResource;
 import com.cloud.service.ServiceOfferingVO;
 import com.cloud.service.dao.ServiceOfferingDao;
 import com.cloud.utils.DateUtil;
@@ -63,7 +66,7 @@ import com.cloud.vm.VirtualMachine.State;
 import com.cloud.vm.dao.VMInstanceDao;
 
 @Local(value = CapacityManager.class)
-public class CapacityManagerImpl implements CapacityManager, StateListener<State, VirtualMachine.Event, VirtualMachine>, Listener {
+public class CapacityManagerImpl implements CapacityManager, StateListener<State, VirtualMachine.Event, VirtualMachine>, Listener, ResourceListener {
     private static final Logger s_logger = Logger.getLogger(CapacityManagerImpl.class);
     String _name;
     @Inject
@@ -107,6 +110,8 @@ public class CapacityManagerImpl implements CapacityManager, StateListener<State
 
     @Override
     public boolean start() {
+    	_resourceMgr.registerResourceEvent(ResourceListener.EVENT_PREPARE_MAINTENANCE_AFTER, this);
+    	_resourceMgr.registerResourceEvent(ResourceListener.EVENT_CANCEL_MAINTENANCE_AFTER, this);
         return true;
     }
 
@@ -698,4 +703,54 @@ public class CapacityManagerImpl implements CapacityManager, StateListener<State
         return false;
     }
 
+	@Override
+	public void processCancelMaintenaceEventAfter(Long hostId) {
+		updateCapacityForHost(_hostDao.findById(hostId));		
+	}
+
+	@Override
+	public void processCancelMaintenaceEventBefore(Long hostId) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public void processDeletHostEventAfter(HostVO host) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public void processDeleteHostEventBefore(HostVO host) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public void processDiscoverEventAfter(
+			Map<? extends ServerResource, Map<String, String>> resources) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public void processDiscoverEventBefore(Long dcid, Long podId,
+			Long clusterId, URI uri, String username, String password,
+			List<String> hostTags) {
+		// TODO Auto-generated method stub
+		
+	}
+
+	@Override
+	public void processPrepareMaintenaceEventAfter(Long hostId) {		
+		_capacityDao.removeBy(Capacity.CAPACITY_TYPE_MEMORY, null, null, null, hostId);
+		_capacityDao.removeBy(Capacity.CAPACITY_TYPE_CPU, null, null, null, hostId);
+	}
+
+	@Override
+	public void processPrepareMaintenaceEventBefore(Long hostId) {
+		// TODO Auto-generated method stub
+		
+	}
+
 }
diff --git a/server/src/com/cloud/resource/ResourceManager.java b/server/src/com/cloud/resource/ResourceManager.java
index e9c79f71ad2..f54b5d7c802 100755
--- a/server/src/com/cloud/resource/ResourceManager.java
+++ b/server/src/com/cloud/resource/ResourceManager.java
@@ -131,4 +131,6 @@ public interface ResourceManager extends ResourceService{
     String getHostTags(long hostId);
     
     List<PodCluster> listByDataCenter(long dcId);
+
+	List<HostVO> listAllNotInMaintenanceHostsInOneZone(Type type, Long dcId);
 }
diff --git a/server/src/com/cloud/resource/ResourceManagerImpl.java b/server/src/com/cloud/resource/ResourceManagerImpl.java
index 85928d7c2ff..a4e86c87b02 100755
--- a/server/src/com/cloud/resource/ResourceManagerImpl.java
+++ b/server/src/com/cloud/resource/ResourceManagerImpl.java
@@ -1100,7 +1100,7 @@ public class ResourceManagerImpl implements ResourceManager, ResourceService, Ma
         try {
             processResourceEvent(ResourceListener.EVENT_PREPARE_MAINTENANCE_BEFORE, hostId);
             if (maintain(hostId)) {
-                processResourceEvent(ResourceListener.EVENT_CANCEL_MAINTENANCE_AFTER, hostId);
+                processResourceEvent(ResourceListener.EVENT_PREPARE_MAINTENANCE_AFTER, hostId);
                 return _hostDao.findById(hostId);
             } else {
                 throw new CloudRuntimeException("Unable to prepare for maintenance host " + hostId);
@@ -1926,6 +1926,17 @@ public class ResourceManagerImpl implements ResourceManager, ResourceService, Ma
 	    return sc.list();
     }
 
+	@Override
+    public List<HostVO> listAllNotInMaintenanceHostsInOneZone(Type type, Long dcId) {
+		SearchCriteriaService<HostVO, HostVO> sc = SearchCriteria2.create(HostVO.class);
+		if (dcId != null){
+			sc.addAnd(sc.getEntity().getDataCenterId(), Op.EQ, dcId);
+		}
+		sc.addAnd(sc.getEntity().getType(), Op.EQ, type);
+		sc.addAnd(sc.getEntity().getResourceState(), Op.NIN, ResourceState.Maintenance, ResourceState.ErrorInMaintenance, ResourceState.PrepareForMaintenance, ResourceState.Error);
+	    return sc.list();
+    }
+	
 	@Override
     public List<HostVO> listAllHostsInOneZoneByType(Type type, long dcId) {
 		SearchCriteriaService<HostVO, HostVO> sc = SearchCriteria2.create(HostVO.class);