4 Expert Tips for High Availability and Disaster Recovery of Your Cloud Deployment
Learn how to continue operating uninterrupted despite downtime with high availability (HA) and disaster recovery (DR) approaches.
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Business continuity is the company’s capability to continue operating uninterrupted despite downtime. In the cloud context, this typically includes high availability (HA) and disaster recovery (DR).
Their ultimate goal is to minimize all downtime risks as much as possible so that you can operate key services normally despite outages.
Read on to learn more about HA and DR and how to boost your business continuity in the cloud.
What Does High Availability Mean?
The basic idea of high availability is to make your cloud-based services and tools accessible and working as required. However, the concept of HA refers to something far more specific than just making your cloud resources readily available when you need them.
Availability is the percentage of time your cloud infrastructure remains operational to serve its purpose, and it is usually expressed in nines. For instance, “five times nine” means that a system operates fully 99.999% of the time and has, on average, 5.5 minutes of downtime per year.
If you wish to achieve high availability for your cloud deployment, you need to eliminate single points of failure through system redundancy. HA also requires orchestrating cloud systems to automatically route network traffic and reduce downtime for your users and applications.
What Does Disaster Recovery Mean?
Disaster recovery is the process of anticipating and addressing issues that may take IT systems down.
DR can be as simple as restoring from a backup, but it can also be more complex depending on Recovery Time Objective (RTO) and Recovery Point Objective (RPO).
- RTO is the maximum period of time that a system can be down before it is fully operational again. Some setups can be down for hours or even days without harm, but for mission-critical elements, the RTO is often measured in seconds.
- RPO is the amount of data loss that is tolerable. While losing a day’s worth of data might be acceptable in some setups, in more critical systems, this might be minutes.
The tolerable lengths of RTO and RPO significantly impact your disaster recovery plan. The shorter they need to be, the more attention you must pay to factors like active data replication, more redundancy, or more frequent backups.
All these translate into higher bills — and the cost is often the main factor stopping organizations from pushing for high availability and short RTOs and RPOs. Reaching a sweet spot requires balancing expenses and the impact of potential system downtime — in some cases, HA and short DR values may be unnecessary.
Here are four expert tips to help you enhance your cloud deployment’s business continuity.
Four Tips for High Availability and Disaster Recovery
1. Operational Observability
Understanding the overall health of your cloud deployment is critical to the high availability of cloud environments.
Operational observability refers to the ability to aggregate logging, metrics, and tracing together with tools for diagnosing and troubleshooting issues.
As a rule of thumb, your cloud deployment should integrate logging and critical metrics for visualization, alarms, and notifications.
To this end, you can use your cloud service provider’s native monitoring and observability tools. For example, AWS has a toolset called CloudWatch, GCP — Google Cloud’s Operations Suite (formerly StackDriver), and Azure — Azure Monitor. However, these aren’t free, and their cost depends on the number of metrics and the amount of processed log data.
You can also choose from numerous third-party tools like DataDog, New Relic, Dynatrace, and more. Open-source solutions from Grafana and Elasticsearch are also popular choices.
Once you choose the right tool for your needs, it’s best to deploy it through Infrastructure as Code (IaC).
2. Use IaC for Backup and Restore
One significant advantage of running IaC tooling is that it lets you recreate all final artifacts and components in the cloud for a full recovery.
With IaC, you only need traditional backup/restore procedures at the Git repository level. Sensitive backup activities must shift to ensuring that you have a sufficient backup strategy for the code repositories. You can achieve this with Git tooling and cross-regional storage solutions.
Each regional cloud deployment contains data that needs a backup. There are various storage solutions that applications such as File Systems, Object Storage Buckets, and Block Storage Volumes can use.
Each artifact requires a backup and retention policy separate from your cloud deployment. You will need to address them for each migrated application and associated storage components.
3. Use IaC for Disaster Recovery
Another significant advantage of IaC is that it enables the automated recreation of entire cloud regions with minimal human intervention.
However, to meet your required RTO and RPO, you may need a data synchronization solution.
Your deployment should include a cold-standby cloud region with a minimally defined infrastructure. The key objective is to synchronize storage and databases for critical infrastructure components and any application-specific storage and database assets.
4. Learn How to Bootstrap a Region
Let’s imagine a scenario where your entire cloud region goes down. You aim to have a documented Mean-Time-To-Recovery for your cloud deployment, ideally measured in hours, not days or weeks.
The ability to quickly bootstrap a region proves that you can recover fast from high-impact availability events. Instantiating a deployment can help, especially since there are only a few hard prerequisites related to networking connectivity.
Even with missing data center connectivity, you can still bring up and tear down most of your cloud deployment components in rapid succession during testing. Your goal should be to create a repeatable process driven through GitOps and Infrastructure as Code.
High availability and disaster recovery both target the same issue: keeping cloud systems up and running despite outages and other odds.
While HA deals with issues within an operational system, DR focuses on recovering it after its failure. Together, they boost your business continuity and help ensure that your cloud deployment remains fully operational.
We hope the four tips above will inspire your cloud migration strategy and make it smoother.
Published at DZone with permission of Leon Kuperman. See the original article here.
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