With converged infrastructure systems, vendors hope to simplify IT by bundling three key data center stack components...
-- compute, storage and networking -- into a single offering that can be deployed quickly. These converged bundles appeal to data centers that have more pressure on them to bring applications or projects into production quickly, rather than wringing every penny out of hard IT costs.
The first step in selecting a converged architecture is to understand all the capabilities of the alternatives.
Two of the primary benefits of converged infrastructure systems are enhanced time to production and a potential for cost savings. A third factor may be that an organization will find value in having compute, storage (capacity and performance) and networking scale in parallel with each other. Another consideration may be having the ability to use existing hardware or to determine the specific hardware purchases you wish to make.
If time to production is paramount, bundled or fully integrated solutions will likely best meet that need. But you need to keep in mind that a fast deployment comes with a higher price and with no ability to integrate existing or alternative hardware. Integrated solutions, because they tend to use commodity hardware, typically strike the best balance between cost and time to production. When cost savings or hardware flexibility is the primary concern, and the organization is willing to invest the time, a software-based converged solution may be most appropriate.
Practically all converged infrastructures run with a hypervisor of some sort. If your data center has already selected VMware and it's the only hypervisor you're using, you'll have the widest variety of choices. If support for a different hypervisor or for multiple hypervisors is needed, or if you wish to integrate bare-metal (nonvirtualized physical server) systems, then a little more investigation is required.
Many of the bundled and integrated solutions can run a hypervisor other than VMware, most typically Microsoft Hyper-V, but not many can run two different hypervisors at the same time. In other words, it becomes an either/or situation.
Bare-metal system integration
If you need to integrate current bare-metal systems into the converged architecture, software-only solutions can satisfy that requirement. There are a few software-only solutions that will allow a physical server to access the shared storage being aggregated by the converged infrastructure. Some may also allow the physical server to contribute capacity to the aggregated volume.
The role of flash in a converged infrastructure
Flash storage can play a significant role in any converged infrastructure architecture. Since most converged architectures support a high number of virtual machines (VMs) per host, the primary role of flash is to allow the architecture to deal with the random I/O storms these environments can create.
For most of the bundled solutions, flash storage is simply a tier on the shared storage system. Some of the more customized solutions leverage the fact that they are server-side and ensure the data for each VM is stored on a flash storage area inside the host the VM is running on. That approach not only provides flash-based access to data, but it does so locally, thus eliminating network latency.
Understand the limitations of converged systems
Converged infrastructures are certainly worth checking into. They can reduce time to virtualization and production, reduce storage costs and increase a data center's ability to scale. But they should be approached with a full understanding of their limitations as well as their benefits. A traditional shared storage infrastructure can offer many of the same advantages as a converged infrastructure plus provide the advantage of dedicated storage performance.
About the author:
George Crump is president of Storage Switzerland, an IT analyst firm focused on storage and virtualization.
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