Server consolidation has been the focus of virtualization, requiring hardware abstraction to create an environment that can run multiple operating systems. Applications run on virtual machines abstracted away from the hardware. Virtualization may reduce the number of physical servers that have to be managed, but the number of operating systems remains the same, or it may even grow, given the ease at which new systems can be instantiated.
There is no question that virtualization offers major benefits in terms of improved administrator productivity, dramatically lowering the time required to bring up new applications in production, and simplifying the test and development process. However, strictly from the standpoint of lowering operational costs, the benefits of virtualization materialize somewhat indirectly.
The ideal consolidation approach is to host multiple workloads within the scope of a single OS, with some form of workload management tool providing the necessary management of resources. In this case, consolidation lowers operational costs by reducing the number of operating environments that administrators have to manage.
Containerization allows a customer to run multiple copies of the same application and provides greater consolidation density. While similar in concept, virtualization and containerization differ significantly in how they enable multi-tenancy and server consolidation. Virtualization provides a virtualized hardware environment where a guest OS is able to run one or more applications. On the other hand, a container host merely provides a logically isolated runtime environment for the application within the same OS instance. Containers, unlike virtual machines, do not require the overhead of booting, managing and maintaining a guest OS environment. For example, see my blog about Docker.
Database consolidation does not mean placing all of your databases into virtual machines. Virtualization, in many cases, replaces physical silos with virtual silos. That does not reduce your IT complexity.
According to the IT Infrastructure Library (ITIL) a Configuration Item (CI) is defined as any component that needs to be managed to deliver an IT service.
For example, consider how many CIs are present in a data center with 8 databases, each running in its own dedicated environment. There are 8 database environments, 8 operating system images and 1 machine. That is 17 CIs that need to be managed, monitored, patched, and backed up. And that is saying nothing about the average utilization of these assets. We can consolidate the 8 dedicated database environments into a single system installed in multiple-container mode with 8 multitenant database containers. In this example we have reduced our CIs to 3. Database patching and backup are done at the single system level.
SAP HANA system with multitenant database containers feature can contain multiple tenant databases. All tenant databases in the same system share the same system resources (memory and CPU Cores). However, each tenant database is fully isolated with its own database users, catalog, repository, persistence (data files and log files) and database services so that for example, you can run both SAP Business Suite and SAP Business Warehouse (BW) in one SAP HANA system.
With multitenant database containers, you can assign system resource limits (memory and CPU cores) to each tenant database so that higher workload on one tenant database cannot impact other tenant databases. You can also change the allocated resources at any time, based on changing needs of each tenant database. For example, if an SAP Business Suite and SAP BW run on one SAP HANA system, you can increase the resources for the SAP BW during month-ends when there is a need for more reports out of the SAP BW system. You also get the flexibility to backup and recover all tenant databases at once or single tenant database at a time. This means, by running multiple tenant databases in one SAP HANA system and managing them as one, you can lower capital expenditure with better utilization of system resources and operating expenditure with simplified database maintenance.
And yet another thing – You sometimes hear the statement that cloud computing is synonymous with consolidation. It is not! Consolidation is a cornerstone of cloud computing, but the enterprise cloud offers so much more.