Posted by Anna Nicholls on 17-Feb-2020 15:23:28

Active-Active cloud hosting, explained

 CA diagram screengrab

Our cloud hosting platform, CloudActiv, is Active-Active out of the box. But what does that really mean? What is Active-Active cloud architecture? Let’s take a look...

Many cloud platforms will be running from a single site solution. This means one site, in one location. You might have (and should have) resilience in the form of replication within that single site, but if the site goes down, you lose access to your digital assets. 

Unlike a single site cloud solution, Active-Active architecture is essentially two cloud platforms linked together, running simultaneously. This means that any data or online assets that are saved to, modified, or updated on the primary platform, are automatically replicated to a secondary platform. These two platforms, which are geographically separate for resilience, then run identically to provide synchronised hosting environments, and your data can be served from either of these platforms at any given time. 

This means that if the primary hosting location goes down, another instantly takes over and your resources remain up and running without any disruption or downtime. It essentially eliminates the risk of downtime through continuous availability via an automatic failover. 

Let’s get a bit more technical…

When you make a change to data hosted in an Active-Active solution, your virtual machine performs a write-operation which is sent to hosts at both locations simultaneously, and data is then written to the write-cache-tier for optimum performance. The hosts report back to your VM with a  write-acknowledgement, and your VM starts its next task. Next, both hosts destage the write-cache tier to the capacity tier simultaneously, without any impact on your VMs.

This type of solution can eliminate the need for clunky failover mechanisms that switch from primary to backup - which can often take hours to execute - and transform your disaster recovery strategy. Active-Active gives you high availability and built-in disaster recovery. It also provides a level of continuity for scheduled maintenance and outages too, such as updates and patches. It can also minimise costs by reducing the need to build, test and maintain a secondary site which can bring complex and time consuming overheads - resources that could be better spent elsewhere. 

Long-term cost saving is another benefit of built-in disaster recovery. Not only do you save on the initial set-up costs of a dual-site infrastructure, you’re also avoiding the costs of the lost revenues associated with downtime and lasting reputational damage.

So does all of this extra resilience mean you can forget about your backups?

No, you should never forget about your backups. Backups and replications serve different purposes, and are best used in tandem. 

With Active-Active cloud everything on the primary site is copied over to the secondary site so that means that any mistakes are also replicated. Any errors, corruptions or accidental deletions would be instantly copied across in real time, to the secondary site. If this was to happen, a data backup would be needed to restore to the correct version of the file. Valuable for compliance, a backup is usually used to protect against data loss, but doesn’t ensure business continuity. Replication through Active-Active is an effective business continuity tool providing near-instant recovery, but it doesn’t tick the box for historical data copies or to maintain compliance with legislation. So a robust solution would incorporate both backups and replication.If disaster strikes (fire, flood, theft for example) and a business experiences an outage, the financial implications come thick and fast. Having replication in place and the ability to failover to a secondary site means business as usual and the ability to drastically reduce Recovery Time and Recovery Point Objectives (RTO/RPO).

Automatic, seamless continuation of service in the event of an outage, is what we believe cloud should be - as standard, which is why we’re built Active-Active resilience into our CloudActiv platform, at no extra cost to the customer.

If you’d like to learn more about how CloudActiv could benefit your business, get in touch with the team for a demo, or to chat about how Active-Active cloud hosting could work for you. 

Topics: disaster recovery, cloud hosting, data centre, cloud, cloud server hosting

Written by Anna Nicholls

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