Проблема с подключением к базе данных Oracle

Развернул приложение на сервере tomcat, сразу же после этого, соединение устанавливается успешно, но примерно через 1 час не могу подключиться к БД.

Пул соединений использую c3p0, Oracle 12.0.1, в папке apache-tomcat/lib лежит ojdbc7.jar

Настройки с3p0:

<?xml version="1.0" encoding="utf-8" standalone="no"?>
<Context>
<Resource name="jdbc/REP"
             auth="Container"
          type="com.mchange.v2.c3p0.ComboPooledDataSource"
                      user="*****"
          password="******"
          driverClass="oracle.jdbc.driver.OracleDriver"
          jdbcUrl="jdbc:oracle:thin:@(DESCRIPTION=(LOAD_BALANCE=off)(ADDRESS_LIST=(ADDRESS=(PROTOCOL=tcp)(HOST=rep-db01.***.ru)(PORT=1521))(ADDRESS=(PROTOCOL=tcp)(HOST=rep-db02.****.ru)(PORT=1522)))(CONNECT_DATA=(SERVICE_NAME=service_rep)))"
          factory="org.apache.naming.factory.BeanFactory"
                      minPoolSize="15"
                      maxPoolSize="100"
                      acquireIncrement="10"
                      testConnectionOnCheckin="true"
                      testConnectionOnCheckout="true"
                      idleConnectionTestPeriod="30"
                      preferredTestQuery="select 1 from dual"
                      maxIdleTimeExcessConnections="240"
                      unreturnedConnectionTimeout="10000"
                      debugUnreturnedConnectionStackTraces="true"
                      acquireRetryAttempts="0"
                      initialPoolSize="20"
                      dataSourceName="java:/comp/env/jdbc/REP"
                      />
</Context>

В логах вижу следующее:

2017-07-12 11:25:23,217 DEBUG [] An exception occurred while acquiring a poolable resource. Will retry.
java.sql.SQLRecoverableException: ORA-01033: ORACLE initialization or shutdown in progress
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:450)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:392)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:385)
    at oracle.jdbc.driver.T4CTTIoauthenticate.processError(T4CTTIoauthenticate.java:497)
    at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:522)
    at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:257)
    at oracle.jdbc.driver.T4CTTIoauthenticate.doOSESSKEY(T4CTTIoauthenticate.java:460)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:594)
    at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:666)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:566)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:183)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:172)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:188)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1074)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1061)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1798)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:636)

2017-07-12 11:25:23,249 DEBUG [] Continuing acquisition series. pending_acquires [20],  attempts_remaining: 9
2017-07-12 11:25:23,249 DEBUG [] com.mchange.v2.async.ThreadPoolAsynchronousRunner@3b3f4e1e: Adding task to queue -- com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@769e5eb6
2017-07-12 11:25:23,370 DEBUG [] Continuing acquisition series. pending_acquires [20],  attempts_remaining: 9
2017-07-12 11:25:23,370 DEBUG [] com.mchange.v2.async.ThreadPoolAsynchronousRunner@3b3f4e1e: Adding task to queue -- com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask@175c3b91
2017-07-12 11:25:23,373 DEBUG [] An exception occurred while acquiring a poolable resource. Will retry.
java.sql.SQLRecoverableException: ORA-01033: ORACLE initialization or shutdown in progress
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:450)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:392)
    at oracle.jdbc.driver.T4CTTIoer.processError(T4CTTIoer.java:385)
    at oracle.jdbc.driver.T4CTTIoauthenticate.processError(T4CTTIoauthenticate.java:497)
    at oracle.jdbc.driver.T4CTTIfun.receive(T4CTTIfun.java:522)
    at oracle.jdbc.driver.T4CTTIfun.doRPC(T4CTTIfun.java:257)
    at oracle.jdbc.driver.T4CTTIoauthenticate.doOSESSKEY(T4CTTIoauthenticate.java:460)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:594)
    at oracle.jdbc.driver.PhysicalConnection.connect(PhysicalConnection.java:666)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:32)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:566)
    at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:134)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:183)
    at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:172)
    at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool$1PooledConnectionResourcePoolManager.acquireResource(C3P0PooledConnectionPool.java:188)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquire(BasicResourcePool.java:1074)
    at com.mchange.v2.resourcepool.BasicResourcePool.doAcquireAndDecrementPendingAcquiresWithinLockOnSuccess(BasicResourcePool.java:1061)
    at com.mchange.v2.resourcepool.BasicResourcePool.access$800(BasicResourcePool.java:32)
    at com.mchange.v2.resourcepool.BasicResourcePool$ScatteredAcquireTask.run(BasicResourcePool.java:1798)
    at com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread.run(ThreadPoolAsynchronousRunner.java:636)