Oracle on Windows

Oracle on Windows supports the same Oracle Disaster Recovery (DR) and High Availability (HA) features as other platforms, such as Oracle RAC and Data Guard. In addition to these, Oracle on Windows supports Oracle Fail Safe. These are all excellent solutions with different usages, costs and performance.

Oracle RAC is a high availability solution that allows multiple Oracle instances to access the same database. This provides for both high availability and additional performance, since all nodes are active. Oracle RAC is an excellent product, but somewhat complicated to install and manage and can be expensive.

In addition to Oracle RAC is Oracle Data Guard. Data Guard is really more of a Disaster Recovery (DR) solution than a High Availability solution, but it can be very useful in the event of a system failure. Data Guard is a fantastic product which I have installed many times. Data Guard is one of those products where the base installation can be fairly straight forward, but there are so many options and modes of operation that it can quite quickly become very complicated.

The final solution in this discussion is Oracle Fail Safe. Fail Safe is a Windows only product that makes Oracle Microsoft Cluster Services (MSCS) aware. Failsafe is available for all Windows platforms (32-bit, x64 and Itanium) and is downloadable from the Oracle web site. Fail Safe is a plug in to MSCS to allow the Oracle instance and listener to be managed under the control of MSCS. This allows the Oracle instance to fail over in the event of a failure of one of the nodes.

The MSCS architecture is very straight forward. Two systems share the same disk, of which only one system controls at a time. In the event of a failure (determined by the heartbeat mechanism), the instance currently running the Oracle instance and controlling the storage is replaced by the standby system. This allows the Oracle database to be back up and running in a matter of minutes, thus improving availability.

Oracle Fail Safe has the advantage over RAC in that it is much easier to implement and administer. Most Windows shops already have implemented MSCS and are very familiar with it. In addition, Oracle Fail Safe is a core feature of Oracle9i and Oracle10g for Windows and no additional license is needed.

With Oracle Fail Safe you can fail over the following Oracle components:

• Oracle Database Server.
• Oracle Listener.
• Oracle Intelligent Agent.

The failover is seamless and works very well. In addition, the management tools allow you to configure Fail Safe to automatically fail back a node at a scheduled time, thus allowing you to configure different hardware resources for the primary and standby servers.

I have worked on multiple Oracle Fail Safe installations. In a Windows environment where you want to have assurance of High Availability at a low entry point cost, Oracle Fail Safe might be for you.

Configuring Oracle Fail Safe is easy once the Microsoft Cluster Services have been installed. The following steps are done in order to install Oracle Fail Safe.

1. Install Windows on both servers.
2. Install MSCS (if applicable) and create the cluster.
3. Install Oracle Database Software on each node’s local disks, using the same Oracle Home directory.
4. Create the Oracle database on one node using the shared disk for storage.
5. Install Oracle Fail Safe on each node in the cluster.
6. Configure the cluster using the Fail Safe manager.
   

You will find that Fail Safe is an easy to use, inexpensive way to provide high availability in a Windows environment.

# posted by Edward Whalen @ 11:13 AM