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To Move or Not to Move: On-Premise vs The Cloud

cloud data warehouse

On-Premise vs The Cloud

The cloud has gracefully matured over nearly two decades, reshaping the IT landscape through a series of evolutionary steps rather than one monumental leap.

Yet, it's essential to recognise that cloud adoption hasn't triggered a complete overhaul; instead, it exists alongside steadfast on-premises systems, each finding their place in the diverse world of business operations.

Barriers to cloud migration have played a pivotal role in this coexistence. Take, for instance, highly regulated sectors like banking, where cloud adoption faced regulatory constraints until late 2018 when APRA revisited its cloud computing policy. Similarly, sizable legacy enterprise systems remained anchored to physical hardware, hindering their migration to the cloud.

However, the tide began to turn as providers re-engineered their platforms towards Software as a Service (SaaS) models, offering a pathway to cloud resources.

For some enterprises, their databases stood as unwavering pillars of reliability, allowing other areas to demand their attention. Yet, time impacts even the most robust systems. With products like SQL Server 2017 passing the end of mainstream support, the imperative to migrate has grown undeniable.

Migrating to the Cloud

When the time comes to make the leap to the cloud, you're met with a multitude of pathways to navigate. Yet, at the core of this journey, two distinct approaches emerge:


Rehosting, often referred to as the "lift and shift" method, stands as a cloud migration approach that requires minimal changes to your existing applications and data architecture. It's often the swiftest route to cloud adoption, making it a prime choice, especially when facing time-sensitive situations, like dealing with a burning platform.


"For some enterprises, their databases stood as unwavering pillars of reliability, allowing other areas to demand their attention. Yet, time impacts even the most robust systems."


In the context of rehosting an on-premise OLAP database, such as SQL Server, within AWS, the process involves the creation of an EC2 instance and the setup of SQL Server. AWS eases this transition with an installation wizard, simplifying the journey further.

Once SQL Server is operational within AWS, the process becomes a matter of performing a full backup of the source system, uploading the backup file to an S3 bucket, and subsequently restoring it to the new destination server. This marks the shift to the cloud. However, it's essential to recognise that you're not fully leveraging the cloud's capabilities at this point. You still operate and pay for servers round the clock, and scaling remains vertical, leading to increased ongoing costs. To unlock the cloud's full potential, you need to consider re-architecting your environment.


The process of re-architecting entails a comprehensive redesign of your environment to harness cloud capabilities, including scalable processing and storage, as well as the ability to pay for resources based on consumption.

Let's revisit the earlier example of an on-premise SQL Server database used for analytical reporting. In a cloud re-architected setup, the logical path often leads to migrating to a Cloud Data Warehouse (CDW) like Snowflake, Redshift, Google Bigquery, Databricks or Synapse, among other available options in the cloud database landscape.

A notable advantage of Cloud Data Warehouses, as exemplified in Snowflake, is the separation of compute and storage costs. With a CDW, you incur charges for each query executed, typically in seconds. Consider a typical analytics setup with data loading processes occurring for 10 minutes each hour between 8 am and 6 pm, and a subsequent 5 minute load to Power BI. In this scenario, your operational hours can be summarised as:

15 minutes per load x 11 loads/day = 2.75 hours/day

This starkly contrasts with the costs associated with maintaining an always-on on-premise or EC2-hosted database.

Another awesome feature of a CDW is the flexibility to scale compute resources. For instance, during data loading, complex transformations may necessitate scaling up to a Medium-sized warehouse to maintain processing efficiency. Meanwhile, your analyst team might concurrently run basic ad-hoc queries, which can comfortably run on a separate Small or even an Extra-Small warehouse, thus minimising your ongoing expenses.

Storage costs in a CDW are entirely independent of compute costs, calculated per TB of data stored. These costs are quite low, hovering around $25 per TB per month for Snowflake hosted within AWS Sydney. Additionally, you can store data within AWS S3 and access it as an external table from Snowflake, offering flexible and cost-effective storage options.

This re-architecting approach not only optimises your cloud usage but also enhances cost efficiency and scalability, making it a strategic choice in your cloud migration journey.

Unleashing the Cloud's Potential

In the realm of cloud migration, where choices abound and transformations beckon, it's crucial to grasp the nuances of your journey to the cloud. As we've explored the two core approaches rehosting and re-architecting, it becomes evident that the decision extends far beyond a mere change in location. It's a pivotal juncture in the evolution of your IT infrastructure.

Rehosting, with its swiftness and simplicity, serves as a lifeline for those facing immediate needs, granting the passage to the cloud with relative ease. Yet, it's a journey that's only partway through the cloud's boundless terrain. Re-architecting, on the other hand, unfolds a world of possibilities—a realm where compute scales dynamically, costs align with consumption, and storage adapts to your needs.

In this ever-evolving landscape, where businesses navigate the delicate balance between tradition and innovation, understanding these cloud migration approaches is paramount. It's not merely about moving to the cloud; it's about harnessing its transformative potential to reshape the way you operate, innovate, and succeed.

So, as you embark on your cloud migration voyage, weigh your options carefully. Consider your goals, your timelines, and your aspirations for a future where the cloud empowers your business to thrive in ways previously unimagined. With the right approach and the right vision, the cloud becomes more than a destination—it becomes the conduit to your organisation's limitless horizons.

For more information get in touch with us via email at or calling 1300 475 510.

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