The systematic approach to addressing these issues and preparing for a disaster before it happens is to set up a disaster recovery strategy. Data security at scale is made simple with the help of the cost-effective, fully managed, policy-based solution known as AWS Backup. The fundamentals of disaster recovery (DR) using AWS best practices will be covered in this post.
A disaster is an occurrence that has a significant negative impact on your organization and prevents a workload or system from achieving its business goal.
Let’s say, hypothetically, you lost all your data. What do you do? You have backups, but are you confident they work? Have you put them to the test? How long will it take to restore all production data? How much revenue have you lost? Does this affect your clientele and reputation?
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Disaster Recovery Strategies on AWS & Recovery Time Objective
You should evaluate the effects of a low-possibility, high-risk incident on your firm as part of your entire strategy to risk management and business continuity. Create a DR plan.
A business impact analysis to determine the financial effects of an interruption to your operations or systems. And a risk analysis that determines the possibility of a disaster and the possible mitigation measures.
- Recovery Time Objective (RTO): RTO indicates how much downtime you can afford. This is the maximum allowable delay between the interruption of service and the restoration of service.
- Recovery Point Objective (RPO): The maximum duration that can be tolerated since the last data recovery point, i.e., how much data you can afford to lose.
You may decide on the best disaster recovery plan for your company and estimate the cost of a disaster recovery solution with the help of a business impact study and a risk assessment.
What is Disaster Recovery on AWS?
Disaster recovery can be set up for both on-premises services and workloads delivered in the Amazon cloud using Amazon Web Services (AWS).
You can use AWS’s four primary disaster recovery (DR) strategies to build backups and replicas that are accessible in the case of a disaster. Each technique has a decreasing recovery time but an increased cost and complexity.
Backup and restore: In a disaster, you can restore your systems from backup by using backups as a starting point.
Pilot light: Keeps essential services functioning in standby mode and activates additional services as necessary in an emergency.
Warm standby: It involves running a full backup system in standby mode using live data replicated from the production environment.
Multi-Site Active/Active: Having a complete backup production system functioning and prepared to handle traffic as and when needed.
Each of these strategies is explained in detail below.
Backup & Restore
The cheapest and easiest strategy for protecting against data loss or corruption is backup and restore. This method can also address the lack of redundancy for workloads deployed to a single Availability Zone or mitigate against a regional disaster by duplicating data to additional AWS Regions.
It is ideal for lower-priority use cases and could serve as a decent starting point if you don’t have a disaster recovery plan. This method is only appropriate for less crucial workloads and systems because RTO and RPO are measured in hours.
You may build automatic restoration to the DR region using the AWS SDK to access AWS Backup APIs. You can schedule this recurring task to start the restoration whenever a backup is finished.
Pilot light
The pilot light strategy entails provisioning a duplicate of your core workload infrastructure and replicating your data from one Region to another. Databases and object storage, which are needed to provide data replication and backup, is permanently on.
A scaled-down core infrastructure is always on with the Pilot Light method, ready to be built to match a genuine production environment. Your database and S3 buckets need data replication enabled for this strategy. Application servers are turned off to save money but are ready for scaling up to the production configuration.
The RTO and RPO of the Pilot Light strategy are typically calculated in minutes or less than an hour, lowering the disaster recovery solution’s cost. It is advised to use a different AWS account for the disaster recovery solution to increase security isolation (e.g., in case security credentials are compromised).
Warm Standby
The warm standby strategy entails ensuring that another Region has a scaled-down copy of the production environment that is still fully functional. Because your task is constantly active in another Region, this strategy extends the pilot light concept and cuts down on the recovery period. This strategy also makes it simpler to conduct testing or create continuous testing, which will boost your confidence in your capacity to bounce back from a disaster.
Note: It’s sometimes challenging to differentiate between warm standby and pilot light. Both comprise an environment with replicas of your major Region assets in your DR Region. The difference is that warm standby can immediately accept traffic (at decreased capacity levels), whereas pilot light must take further action before processing requests.
Multi-site Active/Active
The only method that can almost eliminate downtime and data loss is multi-site active/active, making it the most dependable DR option available. It is, however, the most time-consuming and expensive technique, making it best suited for mission-critical services where downtime or data loss must be tolerated.
It entails continually building parallel infrastructure and data stores that are kept in sync with production and remain dormant until a calamity strikes. Route53, or Global Accelerator, automatically directs traffic towards the DR region and is used to switch between the production and DR regions.
Object Lock
This Amazon S3 feature enables you to store objects using the write-once, read-many (WORM) model. An object lock can prevent items from being removed or overwritten for a set period or permanently. Retention periods and lawful holds are methods of managing item retention offered by Object Lock.
Retention time: Defines the time that an object will remain locked. Your item is WORM-protected during this time and cannot be overwritten or removed.
Legal hold: Offers the same level of security as a retention period but has no time limit. Instead, a legal hold is not released until you specifically do so. Retention times have no bearing on legal holds.
Bottom line
Evaluate your RTO and RPO and test your DR strategy regularly with simulations, regardless of whether you’re starting from scratch or already have backups and a DR plan. The best way to lessen a disaster’s effects is to be prepared for it.
