In the first installment of this blog series, we introduced the concept of disaster recovery (DR) and highlighted six key factors to consider when designing a robust Backup/DR solution. These factors serve as a guide for architects to evaluate and tailor solutions that align with a client’s unique needs and objectives.
In the second part, we took a closer look at the first two factors: the critical distinction between Backups and DR, and the choice between AWS-native and Third-party solutions. These foundational considerations set the stage for understanding the broader landscape of options and how they align with different use cases.
Now, in this third installment, we turn our attention to the remaining factors. Join us as we explore why these factors matter, how they impact the decision-making process, and the role they play in designing a solution that delivers resilience and reliability. Let’s dive in!
Scheduling and Automation
One of the critical factors to consider when designing a backup/DR solution is the level of control and automation the client needs over the backup process. Scheduling and automation capabilities vary widely between solutions, and understanding the client’s expectations is key to selecting the right tool.
Some solutions offer flexible scheduling options, giving clients the ability to define tailored backup policies based on their specific needs. For example, AWS Backup allows users to create custom backup plans where they can specify the frequency (e.g., daily, weekly, monthly), retention periods, and assign different schedules to various resources. Once configured, these backups occur automatically according to the set policies, requiring minimal ongoing management from the client.
In contrast, some solutions provide fixed or limited scheduling options that may not offer the same level of customization. For instance, Elastic Disaster Recovery Service continuously performs block-level replication of source server volumes. While this ensures real-time data protection, it doesn’t provide the client with the ability to set specific backup schedules or retention policies, as the process is designed to operate continuously without manual intervention.
Why It Matters
Failing to address scheduling and automation needs during the design phase can lead to operational inefficiencies or, worse, missed recovery points. For instance:
- If a solution lacks the ability to automate backups during off-peak hours, it might interfere with production workloads.
- Limited retention options could result in insufficient data points for recovery during audits or post-disaster analysis.
By understanding how a client wants to manage the backup process—whether they need granular control or prefer a hands-off approach—you can select a solution that not only meets their operational requirements but also positions them for long-term success.
Physical vs Virtual Servers
A client’s existing infrastructure plays a significant role in determining the appropriate solution. Whether a client’s landscape consists of physical or virtualized servers is another key factor in determining the most fitting Backup/DR solution.
Some tools are versatile enough to cater to both physical and virtual environments, providing flexibility for hybrid infrastructures. For example, Elastic Disaster Recovery Service supports both physical and virtual servers, making it a strong candidate for clients with mixed environments.
Other tools are designed specifically for virtualized environments, limiting their applicability for clients with physical infrastructure. For instance, AWS Storage Gateway is optimized for virtualized environments and works with platforms like VMware ESXi, Hyper-V, and KVM. Similarly, AWS Backup, when used to back up an on-premises environment, requires the environment to be a VMware setup (specifically VMware ESXi).
Third-party solutions often provide extensive compatibility, making them suitable for clients with diverse setups. For example, Acronis supports physical, virtual, and cloud environments, offering a one-size-fits-all approach for hybrid infrastructures. ArcServe has support for VMware ESX/vSphere, Microsoft Hyper-V, Citrix XenServer, and Red Hat EV virtualized environments.
Why it Matters
Selecting a tool that doesn’t align with the client’s current setup can lead to inefficiencies, increased costs, or even the inability to implement a functional solution. By thoroughly understanding the client’s environment and matching it to the capabilities of the solution, you can ensure compatibility, seamless integration, and a tailored approach that addresses both current and future requirements.
RPO/RTO Requirements
Recovery Time Objective (RTO) dictates how quickly systems need to be restored after a failure while Recovery Point Objective (RPO) dictates how much data loss is acceptable. AWS offers a range of DR strategies to meet varying RTO/RPO requirements, each with its own implementation complexity and cost considerations.
- Backup and Restore is best suited for low priority use cases where the client can tolerate longer recovery times. With this strategy, backups are taken periodically, and in the event of failure, systems are restored from these backups. The RTO and RPO for Backup and Restore can be quite high (i.e., several hours), making it suitable for cases where the recovery window is not critical. This strategy typically offers the lowest cost but is less suited for mission-critical applications.
- Pilot Light is ideal for environments that require a moderate RPO/RTO (in the range of 10s of minutes). With Pilot Light, a minimal version of the application runs on AWS at all times. In the event of a failure, the necessary resources are quickly spun up to restore full functionality. This strategy ensures faster recovery than Backup and Restore but still allows for some downtime, which makes it a cost-effective option for many organizations.
- Warm Standby takes the Pilot Light concept further by keeping a scaled-down version of the entire environment always running. This ensures much faster recovery, with RTO/RPO in the range of minutes. The environment is pre-configured, so failover happens quickly, and systems can be rapidly scaled up in the event of a disaster. Warm Standby is a good middle ground for clients who require fast recovery but don’t always need a fully active system.
- Active/Active is the most complex and costly solution, designed for scenarios that demand zero downtime and real-time backups. In an Active/Active setup, systems are fully mirrored across AWS and on-premises (or across multiple AWS regions). This allows for immediate failover with zero disruption to service. The RTO and RPO are close to zero, but this approach incurs the highest costs due to the need for continuous synchronization and infrastructure running at full capacity.
Why it Matters
Different tools align with varying RPO/RTO requirements. For instance, AWS Elastic Disaster Recovery is ideal for scenarios requiring low RPO/RTO, such as Pilot Light or Warm Standby strategies, as it ensures continuous block-level replication of source servers. AWS Backup, on the other hand, is better suited for Backup and Restore use cases, offering flexible backup schedules but longer recovery times. Third-party solutions like Veeam and Zerto provide robust options for Pilot Light and Warm Standby configurations, often including advanced features such as automated failover and failback to support tighter RPO/RTO objectives.
On Premises vs Cloud Restores
The restore process is a critical factor that differs from tool to tool, and the complexity of restoring data to different environments—whether on-premises or in the cloud—varies as well. This difference in complexity, cost, and ease of restore should play a significant role in selecting the right tool for the job.
For example, when backing up data to AWS and later needing to restore it back to an on-premises environment, organizations must consider data transfer costs. Moving large amounts of data from AWS back to the local environment can incur significant bandwidth costs, depending on the amount of data being restored. Additionally, the time required for restoring the data also becomes a key factor, particularly if the transfer involves multiple terabytes or requires the use of slower mediums. This restoration process may introduce delays, which is a crucial consideration for businesses with stringent recovery time objectives (RTOs).
On the other hand, restoring data within AWS presents different challenges. While the cost of transferring data within AWS itself is usually lower than moving data from AWS to an on-premises location, you still need to think about the recovery resources that need to be launched. This includes creating EC2 instances, setting up databases, or even configuring network access to ensure users can interact with the recovered applications and data. Furthermore, if the goal is to continue operations entirely within AWS, you'll need to ensure proper connectivity between the cloud-based recovery resources and any on-premises systems that need to interact with them.
Different tools provide varying levels of support for cloud vs on-premises restores. Some tools offer seamless, automated restores to cloud environments, while others focus more on on-premises environments and might lack cloud-native features or optimizations. For instance, AWS Backup provides strong cloud recovery capabilities but would require additional steps and consideration when restoring back to an on-premises environment. Veeam Backup & Replication, on the other hand, offers more flexibility, supporting restores both to AWS and on-premises environments with robust options for data migration and failover.
Why it Matters
The complexity of the restore process and the associated costs should be factored into the decision-making process when selecting the right disaster recovery tool. If quick restoration to an on-premises environment is required, the tool must support efficient data recovery methods, while tools designed for cloud restores should account for the setup and management of cloud infrastructure during the recovery.
Understanding the nuances of each option—whether considering the cost and complexity of cloud vs on-premises restores—will ensure that the solution is tailored to the client’s operational needs and recovery objectives.
In this post, we’ve explored the remaining key factors to consider when designing a disaster recovery and backup solution, from understanding the complexities of RTO/RPO to weighing the differences between on-premises and cloud restores. Each of these factors plays a crucial role in building a solution that aligns with both technical requirements and business needs.
In our next installment, we’ll return to the case study and apply these factors to analyze the client’s specific requirements, ultimately crafting a tailored solution for their disaster recovery and backup needs. Stay tuned as we turn theory into practice and bring the solution to life.
Ready to see how the puzzle pieces fit together? Let’s dive into the final design in the next blog—don’t miss it!
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