The benefits of server consolidation have been understood for years, with Gartner reporting growing adoption levels as far back as 1998 and virtualisation driving even more consolidation projects in recent years. In a consolidated environment the improved utilisation of servers means that server resources are used more efficiently, performance improves, and hardware requirements are lower, which in turn means lower license costs. It’s a win, win situation.
By consolidating large numbers of smaller servers onto fewer large symmetric multiprocessing (MSP) servers the workload demands on compute power are evened out improving overall utilisation. Large SMP servers simplify the deployment of applications, and less servers to manage means less management overhead, meaning further savings.
One of the main barriers to consolidation was flexibility, with different applications needing different levels of compute, storage and I/O resources, but new SMP servers can be partitioned to an incredibly granular level to dynamically provide processor, memory and I/O resources to applications.
Oracle approaches server consolidation using three main levels of partitioning technology in its SPARC servers; firstly, to use PDoms, or physical domains, which are electrical hardware partitions. A PDom can be powered up or down and changes can be made to it without affecting others. Hardware or software errors are isolated and domains are administered separately, so the effect of an error or security breach on applications is minimal.
At the next level, PDoms can be split down further using Oracle VM Server (OVM) partitioning, creating full virtual machines that run independent instances of the operating system. Each operating system instance contains dedicated CPU, memory, storage and console devices and can run different versions of Oracle Solaris if they need to.
Finally, the most granular level of virtualisation is Oracle Solaris Zones technology, which allows you to create flexible, lightweight zones within a single OS instance, that can be allocated to multiple different applications and managed centrally.
Oracle SPARC customers can layer OVMs on top of PDoms to create another layer of virtualisation which makes it even easier to run large numbers of different workloads on a small number of servers.
In addition to the flexibility offered by the three main technologies, Oracle Enterprise Manager Ops Centre makes management of the consolidated servers simple and straightforward, bringing them all into a single management console.
Oracle offers customers a very flexible way of approaching server consolidation, with its T8, T7, M8 and M7 SPARC servers, and can meet most consolidation requirements simply by using a greater or lesser level of isolation with PDoms and LDoms. This flexibility can make it difficult to know which configuration to use, but by looking at the workloads that are to be deployed and understanding their service levels, resource utilisation characteristics and security requirements, the technology choice becomes clearer. Test and development environments will require a different configuration to production environments.
Customers should aim for as simple and flexible a configuration as necessary whilst taking into account their own need for isolation. The more PDoms and LDoms there are, the more complex an environment is to manage, but the greater the security and availability. The less PDoms and LDoms, the simpler to manage and more efficiently a server will run, but the risks of a single domain failure could be catastrophic and could lead to a greater risk of downtime.
For advice on a specific server consolidation project it is always best to consult an expert who can help map out the goals and objectives before selecting the right technology for the job.
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