How virtual servers make the cloud more elastic
If you're using server virtualisation for more than consolidation, how about aggregation?
By David Marshall | InfoWorld | Published: 13:28, 17 March 2010
The applications that are targeted by virtualisation aggregation are those that get better performance with additional processors or those applications that require files over 64GB. Combining or aggregating multiple x86 servers and their CPUs and memory to create a large virtual machine enabling IT to run compute-intensive applications such as those found in financial analytics, data warehousing, genomics, visualisation, simulation, computer-aided engineering, electronic design, and analysis.
The current solution supports up to 16 x86 server nodes in any configuration. From a software programming perspective, the virtualisation layer supports all variants of Linux running unmodified from their original distribution. In other words, Red Hat Linux runs right out of the box. Once you boot the OS, the system configuration command will expose up to 128 cores and 4TB of memory depending on what you have in each node. The applications will then run unmodified on top of the OS just as though you have a native SMP.
InfoWorld: If you would, explain why someone would virtualise a server for SMP.
ScaleMP: Every enterprise has a high-performance computing need. Big CPU or memory workloads are present, for example, in almost every analytics-driven or data-warehousing environment. In addition, every research organisation has computer-aided design, engineering, or visualisation workloads.
Traditionally these workloads have run on large proprietary SMP systems. These dedicated symmetric multiprocessing (SMP) systems are the dinosaur of IT. They are expensive, often purchased for dedicated applications or workloads, and difficult to repurpose when they become obsolete.
In the absence of an alternative, many customers have been forced to move their SMP code (OpenMP) to a message passing optimised code such as MPI. They've done this in order to take advantage of the price and performance benefits of commodity x86 servers. x86 architecture is much higher performing than the proprietary RISC architectures and are often less than 20% the cost of equivalent systems.
In order to do this with boxes that simply don't have the native SMP scale is to create a high-performance cluster. The benefits of a low-cost, high-performance cluster infrastructure, however, comes at the cost of manageability. Cluster solutions are very complex with each node having their own OS instance, a clustered file system, and, in most cases, moving the code from OpenMP to MPI is not trivial.
Virtualisation for aggregation solutions solves all of these problems.
InfoWorld: And what are some of the benefits that can be enjoyed?
ScaleMP: A virtual SMP enjoys the benefits of the commodity low-cost, high-performance infrastructure without requiring costly software modifications - it will support both OpenMP and MPI codes equally well - but unlike a cluster solution, there is no need for multiple instances of the OS, a clustered file system, separate I/O management, etc.
All of the system node resources are virtualised and optimised to be managed as a single instance. This benefit is so significant that existing high-performance cluster customers have virtualised existing clusters with no cost or performance benefits. What they do enjoy is vastly superior simplified system management value.
Another distinct value for customers considering an x86-based virtual SMP solution is that they can always repurpose the nodes. Because this solution utilises off-the-shelf servers, when the SMP is upgraded or repurposed, the nodes can easily be broken down and reused in another part of the infrastructure.
A cloud solution, for example, is designed specifically to do this: create a dynamic SMP from cloud system resources, run a large SMP workload, and then disaggregate the SMP back into the cloud system pool. This not only provides a tremendous amount of flexibility for cloud IT infrastructure, but it also dramatically improves cloud ROI by extending the number and kind of applications that are able to run in the infrastructure.
InfoWorld: What should companies consider before deploying virtualisation for aggregation?
ScaleMP: The most prevalent reason today for customers to deploy an aggregation solution is simply to take advantage of the power and low-cost infrastructure of commodity systems instead of making a traditional purchase of a large proprietary SMP. However, as customers get a better understanding of their workloads, more and more customers are trying to address these workloads in infrastructure that was never built to run SMP codes.
As enterprise IT looks to deploy cloud infrastructure, they are immediately faced with these applications and workloads. They can either tell the particular internal customers to purchase their own IT solutions, or search for ways to improve the utility of their existing infrastructure. Since the cloud is enabled by virtualisation, using virtualisation to create large SMP is an obvious and congruent decision.