Zimbra not working suddenly.

[pradip]

From last two my zimbra server not responding suddenly in between, Webmail gives a error "Not connected to the server" But at the same time if i check the zmcontrol status showing all services are running.
I don't what is happening. Again if i restart the services using zmcontrol restart - my webmail start working again.

I have check the logs but not able to debug anything out of that.
Please help me out to resolve the issue.

Please reply some on urgent basis, as its disconnecting regularly after 4 to 5 hrs.

[pradip]

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientC onnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up.
at sun.reflect.GeneratedConstructorAccessor16.newInst ance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newI nstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Construc tor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:40 9)
at com.mysql.jdbc.Util.getInstance(Util.java:384)
at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:1015)
at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:989)
at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:984)
at com.mysql.jdbc.SQLError.createSQLException(SQLErro r.java:929)
at com.mysql.jdbc.ConnectionImpl.connectWithRetries(C onnectionImpl.java:2226)
at com.mysql.jdbc.ConnectionImpl.createNewIO(Connecti onImpl.java:2127)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImp l.java:774)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connect ion.java:49)
at sun.reflect.GeneratedConstructorAccessor14.newInst ance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newI nstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Construc tor.java:513)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:40 9)
at com.mysql.jdbc.ConnectionImpl.getInstance(Connecti onImpl.java:375)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonReg isteringDriver.java:289)
at java.sql.DriverManager.getConnection(DriverManager .java:582)
at java.sql.DriverManager.getConnection(DriverManager .java:154)
at org.apache.commons.dbcp.DriverManagerConnectionFac tory.createConnection(DriverManagerConnectionFacto ry.java:78)
at com.zimbra.cs.db.ZimbraConnectionFactory.createCon nection(ZimbraConnectionFactory.java:66)
at org.apache.commons.dbcp.PoolableConnectionFactory. makeObject(PoolableConnectionFactory.java:582)
at org.apache.commons.pool.impl.GenericObjectPool.bor rowObject(GenericObjectPool.java:1158)
at org.apache.commons.dbcp.PoolingDataSource.getConne ction(PoolingDataSource.java:106)
at com.zimbra.cs.db.DbPool.getConnection(DbPool.java: 295)
... 39 more
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsExce ption: Communications link failure

Above is the error found in mailbox.log, please somebody help me out to resolve the problem.