Data Replication in the Cloud and On-Premises

Real-Time Data Replication for High Availability

What is Data Replication?

Data replication is the process by which data residing on a physical/virtual server(s) or cloud instance (primary instance) is continuously replicated or copied to a secondary server(s) or cloud instance (standby instance). Organizations replicate data to support high availability, backup, and/or disaster recovery.  Depending on the location of the secondary instance, data is either synchronously or asynchronously replicated. How the data is replicated impacts Recovery Time Objectives (RTOs) and Recovery Point Objectives (RPO).

For example, if you need to recover from a system failure, your standby instance should be on your local area network (LAN). For critical database applications, you can then replicate data synchronously from the primary instance across the LAN to the secondary instance. This makes your standby instance “hot” and in sync with your active instance, so it is ready to take over immediately in the event of a failure. This is referred to as high availability (HA).

In the event of a disaster, you want to be sure that your secondary instance is not co-located with your primary instance. This means you want your secondary instance in a geographic site away from the primary instance or in a cloud instance connected via a WAN. To avoid negatively impacting throughput performance, data replication on a WAN is asynchronous. This means that updates to standby instances will lag updates made to the active instance, resulting in a delay during the recovery process.

Why Replicate Data to the Cloud?

There are five reasons why you want to replicate your data to the cloud.

  1. As we discussed above, cloud data replication keeps your data offsite and away from the company’s site. While a major disaster, such as a fire, flood, storm, etc., can devastate your primary instance, your secondary instance is safe in the cloud and can be used to recover the data and applications impacted by the disaster.
  2. Cloud data replication is less expensive than replicating data to your own data center. You can eliminate the costs associated with maintaining a secondary data center, including the hardware, maintenance, and support costs.
  3. For smaller businesses, replicating data to the cloud can be more secure especially if you do not have security expertise on staff. Both the physical and network security provided by cloud providers is unmatched.
  4. Replicating data to the cloud provides on-demand scalability. As your business grows or contracts, you do not need to invest in additional hardware to support your secondary instance or have that hardware sit idle if business slows down. You also have no long-term contracts.
  5. When replicating data to the cloud, you have many geographic choices, including having a cloud instance in the next city, across the country, or in another country as your business dictates.

Why Replicate Data Between Cloud Instances?

While cloud providers take every precaution to ensure 100 percent up-time, it is possible for individual cloud servers to fail as a result of physical damage to the hardware and software glitches – all the same reasons why on-premises hardware would fail. For this reason, organizations that run their mission-critical applications in the cloud should replicate their cloud data to support high availability and disaster recovery. You can replicate data between availability zones in a single region, between regions in the cloud, between different cloud platforms, to on-premise systems, or any hybrid combination.

SIOS Real-Time Cloud Data Replication for High Availability and Disaster Recovery

SIOS Datakeeper™ uses efficient, block-level, data replication to keep your primary and secondary instances synchronized. If a failover happens, the secondary instance(s) continues to operate, providing users with access to the most recent data. With SIOS solutions, RPO is always zero and RTO is dependent on the application but typically 30 seconds to a few minutes.

SIOS products uniquely protect any Windows- or Linux-based application operating in physical, virtual, cloud or hybrid cloud environments and in any combination of site or disaster recovery scenarios, enabling high availability and disaster recovery for applications such as SAP and databases, including Oracle, HANA, MaxDB, SQL Server, DB2, and many others. The “out-of-the-box” simplicity, configuration flexibility, reliability, performance, and cost-effectiveness of SIOS products set them apart from other clustering software.

In a Windows environment, SIOS DataKeeper Cluster Edition seamlessly integrates with and extends Windows Server Failover Clustering (WSFC) by providing a performance-optimized, host-based data replication mechanism. While WSFC manages the software cluster, SIOS performs the data replication to enable disaster protection and ensure zero data loss in cases where shared storage clusters are impossible or impractical, such as in cloud, virtual, and high-performance storage environments.

In a Linux environment, SIOS LifeKeeper and SIOS DataKeeper provide a tightly integrated combination of high availability failover clustering, continuous application monitoring, data replication, and configurable recovery policies, protecting your business-critical applications from downtime and disasters.


Here is a real-world example of how one leading manufacturing company uses SIOS to create a high availability solution in the cloud using real-time data replication.

How to Achieve HA in a Cloud Environment with Real-Time Data Replication

Bonfiglioli is a leading Italian design, manufacturing, and distribution company, specializing in industrial automation, mobile machinery, and wind energy products and employing over 3,600 employees in locations around the globe. To run its business, the company relies on various mission-critical applications, including its SAP ERP system. The company’s IT infrastructure includes an on-premises VMware data center and a remote data center for business continuity and disaster protection. Since most of their applications run in a Windows environment, Bonfiglioli used guest-level Windows Server failover clustering in their VMware environment to provide high availability and disaster protection.

The company’s IT team implemented a program to move part of its IT operations into the Microsoft Azure cloud and to leverage Azure as their disaster recovery site. An important requirement of the company’s migration plan was to ensure the cloud architecture could provide better high availability protection than before and ensure Bonfiglioli could continue to meet its strict Service Level Agreements (SLAs).

In its on-premises environment, the company uses VMware clustering, which allows Windows Server Failover Clustering (WSFC) to manage failover to a secondary server in the event of an infrastructure failure. However, it was a challenge to provide this type of protection in the cloud because using guest-clustering with shared-bus disks is not a viable cloud solution. Creating a cluster in VMware using Raw Device Mapping and shared-bus disks (RDM) is challenging and creates limitations for backing up the virtual machines.

The Solution

After evaluating several solutions, Bonfiglioli chose SIOS DataKeeper as their cloud high availability and disaster recovery solution upon learning that SIOS DataKeeper is the only certified high availability clustering solution for SAP in a public cloud. In addition, Bonfiglioli’s management consulting partner, BGP, had experience with SIOS DataKeeper and knew that it is easy to install, transparent to the operating system, and a proven, highly effective solution.

With SIOS, the IT team fashioned a cluster environment without RDM. They created a two-node cluster in VMware and added SIOS DataKeeper Cluster Edition to synchronize storage via real-time data replication in each cluster instance. In an on-premises environment, synchronized storage appears to WSFC as a single shared storage disk.

SIOS DataKeeper also provides high availability protection for the company’s SAP instance and eliminates single point of failure. Using SIOS DataKeeper, the IT team replicated an SSD-tiered disk partition in the company’s on-premises data center using real-time data replication. This allows Bonfiglioli to restore their virtual machines to Microsoft Azure in the event of a disaster.

The Results

Daniele Bovina, Systems Architect at Bonfiglioli, comments about the results, “SIOS DataKeeper gave us an easy way to move our business-critical SAP system to the Microsoft Azure cloud while meeting our stringent SLAs for availability, disaster recovery, and performance.”


For more information about SIOS Clustering Solutions, contact us or request a free trial.


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