In this multi-cloud environment, we used Oracle Data Guard and MegaPort technology to enable reliable failover of critical databases across Oracle Cloud Infrastructure (OCI) and Amazon Web Services (AWS). Today, maintaining business continuity and ensuring IT resilience is a top priority for IT leaders. Enterprises from a wide range of industries are increasingly implementing multi-cloud solutions to enjoy best-in-class service, competitive pricing, agility, flexibility, and increased availability, while enhancing risk management and avoiding reliance on a single vendor. Megaport is a global network-as-a-service provider that provides private interconnection to major cloud service providers. You can take advantage of MegaPort's multi-cloud services to establish a private, cross-cloud connection between your primary Oracle database in AWS and your standby Oracle database in OCI. Oracle Data Guard ensures high availability, data protection, and disaster recovery for critical application data. With Data Guard, you can manually implement failover from the primary database to the standby database through the Data Guard Broker Command Line Interface (DGMGRL) or Oracle Enterprise Manager, or by configuring Fast-Start Failover (FSFO). The architecture showcases Data Guard configurations across OCI and AWS. Deploying an on-premises standby database ensures high availability during local failures and planned maintenance. Standby databases across cloud providers ensure disaster recovery, greater resiliency, and simplify data migration. The following diagram illustrates this reference architecture. 
The schema consists of the following components:GeographyAn Oracle Cloud Infrastructure geography is a local geographic region that contains one or more data centers, known as availability domains. Regions are independent of each other and may be far apart (across countries or even continents).
Availability domainsAn availability domain is an independent, autonomous data center within a region. The physical resources in each availability domain are isolated from the resources in the other availability domains, which provides fault tolerance. Availability domains don't share infrastructure, such as power or cooling systems, or internal availability domain networks. As a result, the failure of one availability domain is unlikely to affect other availability domains in that region.
Virtual Cloud Networks (VCNs) and SubnetsA VCN is a customizable, software-defined network that you set up in an Oracle Cloud Infrastructure region. Like traditional data center networks, VCNs give you complete control over your network environment. A VCN can have multiple non-overlapping CIDR blocks, and you can change them after you create the VCN. You can divide a VCN into subnets, which can cover a region or an availability domain. Each subnet includes a series of addresses that do not overlap with other subnets in the VCN. You can change the size of the subnet after it is created. Subnets can be public or private.
fastconnectOracle Cloud Infrastructure FastConnect provides an easy way to create a private, private connection between your data center and Oracle Cloud Infrastructure. Compared to internet-based connections, FastConnect offers higher bandwidth options and a more reliable network experience.
Dynamic Routing Gateway (DRG).A DRG is a virtual router that provides a path for VPC traffic between a VCN and a network outside a region, such as a VCN in another Oracle Cloud Infrastructure region, an on-premises network, or another cloud provider's network.
vmdb systemOracle VM Database System is Oracle Cloud Infrastructure (OCI) database service that enables you to build, scale, and manage full-featured Oracle Databases on virtual machines. VM database systems use OCI block volume storage instead of local storage and can run Oracle Real-Time Application Clusters (Oracle RAC) to improve availability.
data guardOracle Data Guard provides a comprehensive set of services for creating, maintaining, managing, and monitoring one or more standby databases, enabling production Oracle databases to remain available without interruption. Oracle Data Guard maintains these standby databases as replicas of the production databases. Then, if the production database is unavailable due to a planned or unplanned outage, Oracle Data Guard can switch any standby database to the production role, minimizing outage-related downtime.
ObserverAn observer is a compute node that has configured the necessary Oracle database software and is able to start a fast-start failover (FSFO) of the Oracle database in a Data Guard configuration. Including an FSFO observer in your deployment eliminates the manual intervention required in the event of a database failover and reduces overall downtime.
Object storageObject storage provides quick access to large amounts of structured and unstructured data, including database backups, analytics data, and rich content such as images and **. You can store your data securely and reliably, and then retrieve it directly from within the internet or cloud platform. You can seamlessly scale your storage without experiencing degradation in performance or service reliability. For "hot" storage that you need fast, immediate, and frequent access, use standard storage. For "cold" storage that you keep for long periods of time and have little or no access, use archive storage.
GeographyAn Amazon Web Services geography is a local geographic region that contains one or more data centers, known as Availability Zones. Regions are independent of each other and may be far apart (across countries or even continents).
Availability ZonesAn Availability Zone is one or more independent data centers within an AWS Region that have redundant power, networking, and connectivity. Availability zones enable customers to run production applications and databases that are more available, fault-tolerant, and scalable, which is not possible in a single data center.
Virtual Private CloudvpcA virtual private cloud is a virtual network that you create in an Amazon Web Services region.
direct connectDirect Connect is a private network circuit between the VPC and the AWS external network. It provides stable throughput and low latency, bypassing the public internet. This is AWS's counterpart to Oracle Cloud Infrastructure FastConnect.
Transit Virtual Interface (VIF).The brokered virtual interface allows you to access one or more Amazon VPC transit gateways associated with a Direct Connect gateway. You can use the brokered virtual interface with an AWS Direct Connect connection of 1 2 5 10 Gbps.
Direct Connect Gateway (DGW).The Direct Connect gateway builds on the capabilities of a VPC and adds the ability to connect up to 10 VPCs across geographies.
Transit gateway (TGW).The transit gateway connects the VPC and the on-premises network through a central hub. This simplifies your network architecture and puts an end to complex peer-to-peer relationships. It acts as a cloud router and only needs to be established once for each new connection.
Amazon Simple Storage Service (Amazon S3).Amazon Simple Storage Service is AWS's counterpart to Oracle Cloud Object Storage Service. You can use it to store data, such as oracle database backups.
Software-Defined Networking (SDN).MegaPort's on-demand global software-defined network (SDN) enables fast, flexible, and secure connectivity to the world's top cloud service providers, including Oracle Cloud Infrastructure, Amazon Web Services, Microsoft Azure, and Google Cloud, in more than 750 locations across North America, Asia Pacific, and Europe.
MegaPort Cloud Router (MCR).MegaPort Cloud Router is a virtual routing service designed for cloud-to-cloud connectivity that provides a Layer 3 private connection. From any routing area of Megaport, you can connect to critical cloud and hosting services without hardware. MCR allows you to route data between cloud providers without having to whirlwind traffic to the data center or your on-premises environment.
MegaPort Virtual Cross-Connect (VXC).Once the MCR is configured, you can create virtual cross-connections to connect to services on the MegaPort network without any physical infrastructure. VXC is a private, point-to-point Ethernet connection that connects an A-side, such as your MCR, to a B-side, such as OCI FastConnect, AWS Direct Connect, or Azure ExpressRoute.
The following recommendations can be used as a starting point for setting up Oracle Data Guard in your multicloud environment. Your needs may differ from the architecture described here. vcnSelect CIDR blocks that do not overlap with any other networks (in Oracle Cloud Infrastructure, your on-premises data center, or other cloud providers) that you intend to set up a private connection to.
Choice of connected locationsThis architecture requires one or more geographies to deploy its components: the Oracle Cloud Infrastructure (OCI) region and its associated Oracle Cloud Infrastructure FastConnect edge nodes, the Amazon Web Services (AWS) region and its associated AWS Direct Connect edge nodes, and the Megaport Cloud Router (MCR) location. To achieve the best end-to-end latency, Oracle recommends that you choose a neighborhood metro with these architectural elements. The MCR is available in 33 metropolises in 13 countries.
High availabilityThis architecture demonstrates a redundant and resilient design that uses dual FastConnect connections and dual AWS Direct Connect or Azure ExpressRoute connections that are routed through dual MegaPort MCRs. For non-production or non-business-critical applications, a single-node architecture may be sufficient. For maximum availability, Oracle recommends that you deploy redundant network resources for each component of your architecture.
Observer positionThe best practice for FSFOs is to run the observer process in a data center that is different from both the primary and standby databases. To achieve this, this reference architecture deploys a primary observer and an alternate observer in a different data center than the hosted database.
Active Data GuardEnable Active Data Guard to benefit from advanced features such as offloading production read-only workloads to a synchronous standby, unique block corruption detection and automatic remediation, rolling upgrades, fast incremental backups, and application continuity.
Alternate backupsCreate a database backup from the standby database to offload the backup load of the host.
Fault domainsIn an OCI Region with only one Availability Domain or an AWS Region with only one Availability Zone, use different fault domains to host the primary, standby, and FSFO observers. A fault domain is a grouping of hardware and infrastructure within an availability domain. Each availability domain has three fault domains for independent power and hardware. When you distribute resources across multiple fault domains, your application can withstand physical server failures, system maintenance, and power failures within the fault domain. Fault domains are not shown in the architecture diagram.
When implementing connectivity across cloud topologies, consider the following factors:PerformanceThe bandwidth of the MegaPort Cloud Router (MCR) scales from 1 Gb to 10 Gb sec, which means that it is able to support the highest data transfer rates supported by cloud service providers. Rate limiting is the aggregate capacity that determines the speed of all connections through the MCR. The MCR bandwidth is shared between the Cloud Service Provider (CSP) connections added to it.
SecurityThe cross-cloud interconnection shown in this architecture is based on private connections and is more secure than the public Internet. You can choose to encrypt this traffic, but it is not encrypted in this schema.
AvailabilityThe MCR is available in 33 metropolitan areas in 13 countries, including: Canada, the United States, France, the United Kingdom, Germany, the Netherlands, Ireland, Sweden, Japan, Singapore, Hong Kong, Australia, and New Zealand.
CostThe total cost of interconnecting across clouds depends on:
Oracle Cloud Infrastructure.
AWS Direct Connect port fees, egress data transfer charges, and Amazon S3 costs.
The cost of MegaPort cloud router and virtual cross-connect from MCR to CSP.
megaport
Amazon Web Services.
oracle
FastConnect and Oracle Object Storage costs. There are no egress fees for Oracle Cloud Infrastructure. The deployment of the MCR is self-service through the MegaPort portal. To deploy this reference architecture, you'll need access to the MegaPort portal, the Oracle Cloud portal, and the AWS or Azure portal. Megaport sets up interconnection points with OCI and AWS.
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