AWS Database reference implementation

This reference implementation provides the architecture and associated CloudFormation templates for a standard, enterprise class, large enterprise class and high performance Oracle 11g configuration on AWS EC2:

http://media.amazonwebservices.com/AWS_RDBMS_Oracle_11g_on_EC2_Reference_Architecture.pdf

RDS cross region snapshots

Great news for AWS RDS users looking to provide extra DR protection to their SQL Server, Oracle and MySQL databases: http://aws.amazon.com/about-aws/whats-new/2013/10/31/announcing-point-and-click-copy-of-amazon-rds-db-snapshots-across-aws-regions/

Oracle RAC on AWS

Oracle Real Application Clusters (RAC) is not natively supported on AWS. The word natively is used because it is possible to run Oracle RAC in an AWS Direct Connect facility http://aws.amazon.com/directconnect/.

There are a number of options when migrating an Oracle RAC database to AWS.  The option you use depends upon the reason RAC is being used.  For HA and fail over, AWS offers multi-AZ capabilities which can provide the same level of service.  For very large databases that require high transaction through put that can not be achieved on a single instance database, Direct Connect would be the solution.  Details on these options are as follows:
1. RDS with multi-AZ :  Oracle RDS is the managed database service from AWS.  Oracle RDS has builtin multi-AZ capabilities.  Because RDS is a managed service, AWS takes care of installation, configuration and management of the secondary database, the replication between AZs, and the fail over and fail back of the database instance.
2. EC2 with multi-AZ :  Running on EC2 requires the customer or partner to install, configure, manage, and take care of the replication.    Oracle Data Guard or GoldenGate can be used for replication.
3. Direct Connect : The AWS partner Datapipe runs RAC in a managed service model using Direct Connect.

Note: Remember that AWS RDS only supports databases up to 6 TB in size. Note this number changed to 6 TB in June 2015 after being 2 TB. https://aws.amazon.com/about-aws/whats-new/2015/06/amazon-rds-increases-storage-limits-to-6TB-for-piops-and-gp2/. Check the whats new web page for any updates related to Oracle on RDS.

Note:  The reason Oracle Real Application Clusters (RAC) is not supported on AWS is:
1. Multicast is not supported on the AWS network. An overlay network is possible on AWS: http://cloudconclave.blogspot.com/2013/06/overlay-networks-on-aws.html
2. AWS EBS is not a shared disk / clustered file system.
So, even if you use a solution such as Amazon EFS, GlusterFS, Zadara, SoftNAS, or custom NFS for shared disk you can not use RAC on AWS as you need multicast support.  More on Amazon Elastic File System (EFS): https://aws.amazon.com/blogs/aws/amazon-elastic-file-system-shared-file-storage-for-amazon-ec2/ 

Oracle Database on EC2 HA environment

Oracle Data Guard can be used to set up one or several slave databases which will be the foundation of a highly available environment. It maintains the standby databases as transaction- consistent copies of the primary database.  These instances can be placed in several availability zones.Then, if the production database becomes unavailable because of a planned or an unplanned outage of this instance or of the full availability zone, Data Guard can switch any standby database to the production role, minimizing the downtime associated with the outage.  It has three protection modes allowing the customers to maximize protection, availability or performance. The Active Data Guard module enables read-only access to the standby databases, thereby allowing customers to run read queries and reports on the standby instances, and to perform the backups from a standby instance.

You can have zero data loss by using the appropriate data protection mode:

http://docs.oracle.com/cd/B28359_01/server.111/b28294/protection.htm#CHDEDGIF

AWS RDS cross region replication

RDS offers a simple way to replicate across AZs (Multi-AZ feature) for fault tolerance and high availability.  RDS cross region synchronization / replication provides additional fault tolerance.  This is an interesting situation because RDS is a 'black box'/PaaS/DaaS environment. Therefore, no access to the OS level is provided. This means this replication solutions like MySQL Replication or Oracle Goldengate can not be used.  Until RDS offers snapshots like the new EBS region snapshotting, you will have to use tools like BitTorrent or CloudBeam to move database dump files across regions.You could use DB links with materialized views as this article mentions: http://aws.amazon.com/articles/4173109646282306. DB Links are slow but if you don't have a low RTO and RPO you could use this...Or come up with your own creative solution.

Oracle Data Guard on EC2

Oracle Data Guard can be used to set up one or several slave databases which will be the foundation of a highly available environment. It maintains the standby databases as transaction- consistent copies of the primary database.  These instances can be placed in several availability zones.Then, if the production database becomes unavailable because of a planned or an unplanned outage of this instance or of the full availability zone, Data Guard can switch any standby database to the production role, minimizing the downtime associated with the outage.   The Active Data Guard module enables read-only access to the standby databases, thereby allowing customers to run read queries and reports on the standby instances, and to perform the backups from a standby instance.

You can have zero data loss by using the appropriate data protection mode:http://docs.oracle.com/cd/B28359_01/server.111/b28294/protection.htm#CHDEDGIF

AWS EBS cross region migration

AWS offers the capability to migrate an EBS volume from one region to another.  The feature applies to any application or database data:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-copy-snapshot.html

This can be used to move Oracle database EBS snapshot from one region to another for HA and DR.

Oracle WebLogic clustering

Active/active high availability with Oracle Weblogic on AWS EC2 can be done with Oracle WebLogic Server clustering.  You must use unicast as multicast is not supported on AWS.

AWS Four DR scenarios

There are four DR scenarios that highlight usage of AWS in a DR and a 'HA-lite' situation:

•  Backup and Restore - For systems running on AWS, customers also back up into Amazon S3. Snapshots of Elastic Block Store (EBS) volumes and backups of Amazon RDS are stored in Amazon S3. Alternatively, you can copy files directly into Amazon S3, or you can choose to create backup files and copy them to Amazon S3.
• Pilot Light for Simple Recovery into AWS - This scenario is similar to a Backup and Restore scenario, however, you must ensure that you have the most critical core elements of your system already configured and running in AWS (the pilot light). When the time comes for recovery, you would then rapidly provision a full scale production environment around the critical core. The database data would be replicated to S3. You would typically have some pre-configured servers bundled as Amazon Machine Images (AMIs), which are ready to be started up at a moment’s notice.  These servers could be EC2 instances that have been stopped.
• Warm Standby Solution - A warm standby solution extends the pilot light elements and preparation. It further decreases the recovery time because in this case, some services are always running. By identifying your business-critical systems, you would fully duplicate these systems on in another AWS zone or region and have them always on.  This would insure that the EC2 capacity is available in a disaster.
•  Active-Active Solution - A multi-site solution runs in another AZ or zone in an active-active configuration. The data replication method that you employ will be determined by the recovery point (RPO) you choose.