1) Increase working buffer size to 1M when downloading/uploading VMDK, hopefully can improve OVF exporting/importing performance. 2) use atomic SQL operation to get rid of global lock usage

server/src/com/cloud/alert/ClusterAlertAdapter.java

@@ -88,31 +88,16 @@ public class ClusterAlertAdapter implements AlertAdapter {
 
         for (ManagementServerHostVO mshost : args.getLeftNodes()) {
             if (mshost.getId() != args.getSelf().longValue()) {
-                GlobalLock lock = GlobalLock.getInternLock("ManagementAlert." + mshost.getId());
+                if(_mshostDao.increaseAlertCount(mshost.getId()) > 0) {
-                try {
-                    if (lock.lock(180)) {
-                        try {
-                            ManagementServerHostVO alertHost = _mshostDao.findById(mshost.getId());
-                            if (alertHost.getAlertCount() == 0) {
-                                _mshostDao.increaseAlertCount(mshost.getId());
-
                     if (s_logger.isDebugEnabled()) {
                         s_logger.debug("Detected management server node " + mshost.getServiceIP() + " is down, send alert");
                     }
-
                     _alertMgr.sendAlert(AlertManager.ALERT_TYPE_MANAGMENT_NODE, 0, new Long(0), "Management server node " + mshost.getServiceIP() + " is down", "");
                 } else {
                     if (s_logger.isDebugEnabled()) {
                         s_logger.debug("Detected management server node " + mshost.getServiceIP() + " is down, but alert has already been set");
                     }
                 }
-                        } finally {
-                            lock.unlock();
-                        }
-                    }
-                } finally {
-                    lock.releaseRef();
-                }
             }
         }
     }

server/src/com/cloud/cluster/dao/ManagementServerHostDao.java

@@ -31,7 +31,7 @@ public interface ManagementServerHostDao extends GenericDao<ManagementServerHost
     boolean remove(Long id);
 
 	ManagementServerHostVO findByMsid(long msid);
-	void increaseAlertCount(long id);
+	int increaseAlertCount(long id);
 	
 	void update(long id, long runid, String name, String version, String serviceIP, int servicePort, Date lastUpdate);
 	void update(long id, long runid, Date lastUpdate);

server/src/com/cloud/cluster/dao/ManagementServerHostDaoImpl.java

@@ -167,21 +167,24 @@ public class ManagementServerHostDaoImpl extends GenericDaoBase<ManagementServer
 	
 	@Override
     @DB
-	public void increaseAlertCount(long id) {
+	public int increaseAlertCount(long id) {
         Transaction txn = Transaction.currentTxn();
         PreparedStatement pstmt = null;
+        int changedRows = 0;
         try {
             txn.start();
             
-            pstmt = txn.prepareAutoCloseStatement("update mshost set alert_count=alert_count+1 where id=?");
+            pstmt = txn.prepareAutoCloseStatement("update mshost set alert_count=alert_count+1 where id=? and alert_count=0");
             pstmt.setLong(1, id);
             
-            pstmt.executeUpdate();
+            changedRows = pstmt.executeUpdate();
             txn.commit();
         } catch(Exception e) {
             s_logger.warn("Unexpected exception, ", e);
             txn.rollback();
         }
+        
+        return changedRows;
 	}
 	
 	protected ManagementServerHostDaoImpl() {

vmware-base/src/com/cloud/hypervisor/vmware/util/VmwareContext.java

@@ -52,6 +52,7 @@ public class VmwareContext {
 	private String _serverAddress;
 	
 	private Map<String, Object> _stockMap = new HashMap<String, Object>();
+	private int _CHUNKSIZE = 1*1024*1024;		// 1M 
 	
 	static {
 		try {
@@ -267,7 +268,7 @@ public class VmwareContext {
 		
 	    InputStream in = conn.getInputStream();
 	    OutputStream out = new FileOutputStream(new File(localFileFullName));
-	    byte[] buf = new byte[102400];
+	    byte[] buf = new byte[_CHUNKSIZE];
 	    int len = 0;
 	    while ((len = in.read(buf)) > 0) {
 	    	out.write(buf, 0, len);
@@ -289,7 +290,7 @@ public class VmwareContext {
 		try {
 		    out = conn.getOutputStream();
 		    in = new FileInputStream(localFile);
-		    byte[] buf = new byte[102400];
+		    byte[] buf = new byte[_CHUNKSIZE];
 		    int len = 0;
 		    while ((len = in.read(buf)) > 0) {
 		    	out.write(buf, 0, len);
@@ -322,8 +323,7 @@ public class VmwareContext {
 		conn.setDoOutput(true);
 		conn.setUseCaches(false);
 		
-		int CHUCK_LEN = 64*1024;
+		conn.setChunkedStreamingMode(_CHUNKSIZE);  
-		conn.setChunkedStreamingMode(CHUCK_LEN);  
 		conn.setRequestMethod(httpMethod);  
 		conn.setRequestProperty("Connection", "Keep-Alive");  
 		conn.setRequestProperty("Content-Type", "application/x-vnd.vmware-streamVmdk");  
@@ -336,7 +336,7 @@ public class VmwareContext {
 			bos = new BufferedOutputStream(conn.getOutputStream());  
 			is = new BufferedInputStream(new FileInputStream(localFileName));  
 			int bytesAvailable = is.available();  
-			int bufferSize = Math.min(bytesAvailable, CHUCK_LEN);  
+			int bufferSize = Math.min(bytesAvailable, _CHUNKSIZE);  
 			byte[] buffer = new byte[bufferSize];  
 			while (true) {  
 				int bytesRead = is.read(buffer, 0, bufferSize);  
@@ -378,7 +378,7 @@ public class VmwareContext {
 	    	in = conn.getInputStream();  
 	    	out = new FileOutputStream(new File(localFileName));  
 	    
-	    	byte[] buf = new byte[64*1024];  
+	    	byte[] buf = new byte[_CHUNKSIZE];  
 	    	int len = 0;  
 	    	while ((len = in.read(buf)) > 0) {  
 	    		out.write(buf, 0, len);  
@@ -406,7 +406,7 @@ public class VmwareContext {
 	    InputStream in = conn.getInputStream();
 	    
 	    ByteArrayOutputStream out = new ByteArrayOutputStream();
-	    byte[] buf = new byte[102400];
+	    byte[] buf = new byte[_CHUNKSIZE];
 	    int len = 0;
 	    while ((len = in.read(buf)) > 0) {
 	    	out.write(buf, 0, len);