If you share your photos on social media, they will stay on the internet forever…

Many of us have heard or read this sentence during conversations with friends, in articles, online forums, TV shows, etc.

But how is it possible that we can’t seem to be able to fully remove our photos from the internet when we want to, and, taking this further, that our photos are never lost and always retrievable (which can both be a good and a bad thing)?

The behind-the-scenes, technical secret lies in data replication.

The very first moment when you share a photo on social media, that photo is uploaded into the closest available database server. In the second moment, that same photo is replicated into multiple other servers around the world.

This is what data …

There are multiple architectures that can be used to achieve highly available database services, each differentiated by the levels of uptime they offer.  These architectures can be grouped into three main categories:
- Data Replication
- Clustered & Virtualized Systems
- Shared-Nothing, Geographically-Replicated Clusters

As illustrated in the figure below, each of these architectures offers progressively higher levels of uptime, which must be balanced against potentially greater levels of cost and complexity each incurs. 

Simply deploying a high availability architecture is not a guarantee of actually delivering HA.  In fact, a poorly implemented and maintained shared-nothing cluster could easily deliver lower levels of availability than a simple data replication solution.

 



To reduce risk and accelerate the evaluation process, …