Cut, copied and pasted from: http://www.sun.com/software/sge/ for future personal reference.

Sun Grid Engine software is the world’s leading – and most widely deployed – distributed resource manager. Sun Grid Engine 6.2 Update 5 brings you even more power and the ability to lower the costs even more than ever before.

Why Sun Grid Engine 6.2 Update 5?
(1) It runs Hadoop Apache as a data center application. No dedicated Hadoop cluster needed.
(2) It is able to schedule applications that are sensitive to CPU topologies to maximize their performance, cutting execution times in some cases by over 50%.
(3) Resources can be automatically rented and provisioned from the Amazon EC2 service to keep up with peak demand. It is much better than buying and keeping them idle during low demand.
(4) It does power conservation by turning off idle systems and turning them on, when demand justifies it.

Features & Benefits
Slot-wise preemption* Preemption makes users unhappy. Therefore, it must be enforced only when absolutely necessary. The concept of the subordinate queue comes from the times when only one core CPU’s were used in clusters. Rather then preempting the entire subordinated queue (Queue-wise subordination), Slot-wise subordination allows preempting individually jobs from a subordinated queue, minimizing the disruption of users work. The ability to more finely enforce subordination policies, results in a more efficient use of resources. It works well in conjunction with Topological-aware scheduling (see below) and thus contributes to higher throughputs.
Array job throttling. Allow users to prevent large jobs from monopolizing a cluster* An SGE Array Job is a task that is to be run multiple times with a single command. This means EXACTLY the same task is going to be run multiple times, usually processing different data segments. The same task processing gets applied on different aspects of a problem. Array Job Throttling allows users to set a self-imposed limit with the maximum number of concurrent running job tasks. The array job may take some tolerable longer time to conclude, but this blocks out less resources for the array jobs and allows other jobs from the same user or other users to run sooner.
Topological-aware scheduling. Performance optimization for multi-core processors, specifically on Nehalem* In the modern multi-core processing, each socket CPU and each core has execution units, cache, memory channels, I/O channels. Under NUMA (Non-Uniform Memory Access) a processor can access its own local memory faster than non-local memory, that is, memory local to another processor or memory shared between processors. Topological Scheduling allows to schedule jobs at core level or CPU level according to its unique needs. The use of Topological Scheduling has resulted in dramatic performance increases.
Data-aware job scheduling. Integration with Hadoop Apache.*,** Ability to schedule jobs in environment with massive scale of data first introduced by the web, now commonplace in many industries (Google, Amazon). Hadoop users have no tools to estimate the cost of running it. SGE changes this. It provides full accounting for Hadoop applications for historical analysis and/or billing purposes.
Cloud Bursting: Service Domain Manager Cloud Adapter *, ** Using SGE 6.2 Update 5, additional resources can be automatically provision from the Amazon EC2 service to process short term peak application workloads. Cloud Bursting brings in the enterprise data center elasticity to customer demand which is a sine-qua-non capability to operate it as a hybrid cloud with greatly reduced costs.
Power conservation: A Cloud Service adapter can be configured for power savings, based on Service Level Os for power savings. New commands such as “showCloudHosts”, “startupCloudHosts” and “shutdownCloudHost” can used to create new power saving scripts.*,** In the data center, when some systems that are not performing any useful work are still consuming power and must be cooled. Sun Grid Engine 6.2 Update 5 software can isolate and power them down when not needed according to the current workload. As workloads increase again, they are automatically powered back up and put into service, with significant power savings.
SGE Inspect supports configuration of Sun Grid Engine Parallel Environments*, ** More ease of use when managing parallel processing workloads with Sun Grid Engine
Exclusive Host Scheduling The cluster can be configured to allow jobs to request exclusive use of various components of a given execution host, An exclusive job will only be scheduled on execution hosts that have no jobs currently running. For a parallel job running on multiple machines, this rule applies for the slave tasks of the job as well. Offers predictable performance guarantees are required. The tight integration of parallel systems is made much easier and can eliminate the need for additional, complex scripts.
Graphical Installer complements the existing command line based installation routine and simplifies initial cluster setup with easy-to-navigate displays. It also verifies installation options. Helps new users to more easily install the software. See video with demo or Podcast Daniel Templeton interviews Lubos Petrik.
Job Submission Verifier (JSV) is an automatic filter for the system administrator to control, enforce and adjust jobs submissions. The basic idea is that on both the client side and the server side, the administrator has the ability to configure scripts that can read through job submission options and accept, reject, or modify the job submission accordingly. JSVs open up a new world of possibilities that didn’t exist before, and it will largely end the need for qsub wrapper scripts. This lowers the barrier for users of High Performance Applications, where small typos or inaccurate resource requests from users can be automatically corrected.
Scalability Scales up to 63,000 core CPUs