In a recent article, I described how an outsource, or hosted provider can deliver Disaster Recovery (DR) as a Service. In this article, I would like to look at the advantages a business can achieve by creating their own Disaster Recovery and answer the question, which option is right for your business. First, a reminder that DR is not a backup of data but rather a replication of data to ensure its availability and business continuity. DR solutions that are created by using the business’s own IT infrastructure can be divided into two primary categories, active-active and active-passive. Since active-passive was covered in the previous blog, I will focus on active-active here. While both attempt to achieve the same goals, keeping the business IT systems up at all times, they are created and maintained differently. Because of the unique nature of DR solutions, it is generally accepted to engage an expert such as Two Ears One Mouth IT Consulting to determine the right DR solution for an organization. I will compare the two DR strategies through complexity, cost and the most common metrics for DR Recovery Time Objective (RTO) and Recovery Point Objective (RPO).
Active-Active Disaster Recovery
An active-active, or stretched clustering, configuration is the deployment of a second identical live infrastructure which continually replicates with the first site. This framework will typically consist of only two sites. Because of the simplicity of the concept and the speed and ease in which recovery can occur, it is usually the clients first choice. Ironically, after all the pertinent information is uncovered, is rarely selected by the small medium business seeking disaster recovery.
The two primary reasons it isn’t chosen for most businesses is its cost and the requirement for high bandwidth with low latency. Its high initial cost is due to the purchase of a duplicated set of hardware infrastructure for the primary site. In an active-active scenario, either site can handle the entire workload for the business. Every time a request is made in a software application at one site it must be written to the other site immediately before completing the request. An active-active solution requires a high level of connectivity, or bandwidth, between sites such as dedicated fiber optics. Even with dedicated (dark) fiber between sites data latency is still a consideration. Best practices dictate that the distance between active-active sites should be less than 100 miles. These two requirements eliminate many prospects from considering an active-active solution.
Advantages of Active-Active
Now I will describe the advantages of an active-active configuration and the businesses that can benefit from it. There are many benefits to this configuration as it is a remarkable process for business continuity. After realizing the upfront cost, many businesses need to determine if it’s a nice-to-have or need-to-have solution for their business. To follow are some of the benefits of an active-active DR solution.
1) No “big red” button to push-
One of the most difficult processes of any DR solution is knowing how and when to declare an IT outage a disaster and quickly executing the DR plan. Many solutions will require a detailed process and action plan that involves the entire IT team. An active-active configuration is much simpler to invoke the DR plan because it transfers all workloads to one of the continually running and replicated systems. In addition, it requires very little testing and can be engaged automatically with minimal human intervention.
2) Cross-site load balancing-
Although it can be simple to transition to DR mode an active-active DR configuration is very complex to design and create. Some of the factors that make it difficult to create are the very same that provide additional benefits beyond DR. On such benefit is “load balancing” of the data transmitted between sites and offsite. Since both sites are always actively processing data it can be designed so that any process being run can occur at the optimal site available at that time. This can eliminate challenges of slow data responses and maximize bandwidth availability for the business.
3) Less management means less cost-
The argument can be made that the active-active DR solution is the more cost effective for the long term. The time and technical resources to test, maintain and initiate an active-passive DR solution is much greater than the active-active. Additionally, in analyzing a DR solution, most don’t consider the operational task to “fallback” to normal mode after DR has been implemented; this can be more difficult than the original DR transition. Although expensive initially, the active-active solution has very little ongoing costs.
Active-Passive Disaster Recovery
An active-passive DR solution creates an environment that is not intended to be live for IT production until a disaster is declared by the business. The infrastructure is over subscribed for resources and dormant until needed. This creates large initial cost savings on hardware. Many times, a business will re-purpose their aged IT equipment and servers for their DR site to realize even greater financial benefit.
One of the most popular active-passive software platforms for disaster recovery today is Zerto. Zerto’s DR solution creates DR at the hypervisor level of the virtualized environment. This allows for a quick and complete transition to the DR resources when an outage occurs. Zerto works with the most popular hypervisors such as VMware or Microsoft’s Hyper V. An active-passive solution such as Zerto can create a more customized solution. A business may select only a small percentage of their application servers as critical to the business and enable DR solution for those applications only. An active-passive solution is more accommodating to multi-site or multi-cloud business DR. Active-passive solutions are also used to provide Disaster Recovery as a Service (DRaaS) from data center and cloud providers.
When a business looks to create DR solution for their business, they have three primary options, active-active, active-passive and DRaaS. It is not a quick or simple decision as to what works best for your business. You need a trusted advisor like Two Ears One Mouth IT Consulting to investigate your IT environment, understand your budget, to guide you down the path to assured business continuity.
If your business is unique and requires a custom DR solution for IT Support
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