Insight Blog

Hybrid cloud deployment with Exasol

Hybrid cloud by Exasol combines the best aspects of on-premise and cloud solutions

Is the cloud an option you can consider when streamlining your enterprise architecture in order to gain a competitive advantage, or is it the wrong choice for your organization? Sometimes the answer is a clear “yes and no.” In such cases, the “hybrid cloud” may be the answer you are looking for.

In general, the hybrid cloud concept combines on-premise (or private cloud) systems with public cloud deployments within one seamless IT landscape.

The most relevant reasons for hybrid cloud in the context of data management systems and database in particular are:

  • Privacy and data protection: Manage sensitive or critical workloads on-premise while storing and using public cloud offerings to manage less-critical information.
  • Performance and availability: Manage data that has to be delivered within sub-seconds using your on-premise high performance hardware while leveraging cost-efficient cloud servers for data with lower requirements in terms of response-time and availability.
  • Data locality: If you generally operate systems in the cloud as well as on-premise it might be not feasible to transfer all the data located in the cloud to on-premise systems and vice-versa to perform analytics that comprises all the data.
  • Cloud Migration: When migrating your IT landscape from on-premise to the cloud or vice-versa, a hybrid cloud approach permits a step-wise migration process: use-case by use case or database table by database table without any service interruption. Users always see a consistent and complete view. For them it’s fully transparent what is in the cloud and what is not.

EXASOL perfectly supports such hybrid cloud scenarios. EXASOL is an database that runs on a cluster of standard servers and is used by companies such as Adidas, Olympus or Zalando for their critical data-driven business operations.

With its new concept of virtual schemas, EXASOL provides a powerful abstraction functionality to integrate and transparently access arbitrary data sources in such hybrid environments.

Just set up one EXASOL database cluster in the cloud, another one on-premise and connect both systems using our virtual schemas technology. Or connect any other data management source in your data center or cloud environments to create one transparent, virtual access layer.

A user who connects to the local EXASOL database will then be able to access the data of the connected database systems, locally and remotely. Therefore, it’s completely transparent where the data is stored and managed.

                                                     Connecting databases using virtual schemas

Think of virtual schemas as a read-only link to an external source that contains virtual tables that look like regular tables except that the data is not stored locally.

When a user executes a query that references a virtually connected schema and a physical schema, EXASOL automatically sends parts of the query to the virtually connected data source. Intelligent pushdown algorithms ensure that as many functions and predicates as possible are executed on the remote system to minimize the amount of data that needs to be transferred between the systems located on-premise and in the cloud.

It looks like a normal schema with data stored in the database the user is interacting with.  But the actual processing is automatically split across the different platforms.

This setup can also be configured in a symmetric way, where the database that is located in the public cloud also virtually integrates the on-premise tables.

                                                   Symmetric hybrid cloud setup using virtual schemas

In general, a virtual schema based hybrid cloud deployment can be implemented using any data management system supported by virtual schemas (e.g. Oracle, SQL Server, Loading...Hadoop or any other ODBC/JDBC-compliant database) in combination with an EXASOL database instance.

EXASOL has decided to publish the virtual schemas extension as open source project on GitHub so that additional adapters to further data sources can easily be shared and extended by the growing EXASOL community. If you’d like to see the power of EXASOL for yourself, download the Free Small Business Edition at

If you are interested in outsourcing your data warehouse and have not yet heard about EXACloud, then learn more about our fully managed database-as-a-service offering in our bare metal cloud at