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Where does the majority of the value reside in a typical enterprise storage array? Is it the software, the hardware or both?
With all the attention and hype around software-defined storage (SDS) lately, the industry seems to be leaning in the direction of software. The noise isn't just coming from small storage startups, either. EMC, HP and IBM, just to name a few, are all offering SDS products.
- Hardware flexibility: Separating storage software from hardware allows organizations greater choice in what hardware they deploy and when they deploy it.
- Access to newer hardware technologies sooner: This flexibility allows for faster or higher-capacity storage to be integrated as soon as the hardware is available, instead of having to wait for a new array to be released four to five years later.
- Simplified license management: There is no need to buy new or upgrade storage software feature licenses when procuring the next generation of hardware.
- Support for multiple generations: The ability to integrate multiple hardware revisions over the lifetime of the system. This allows organizations to incrementally upgrade hardware with data in place, eliminating fork-lift upgrades.
However, there is a potentially hidden cost related to SDS that few in the industry are talking about. The mixing and matching of hardware made possible by SDS can shift the cost -- or the risk -- of integrating the software and hardware to the end-user.
While many like to use the term "commodity hardware," in truth, there is no such thing. I spent a portion of my career as a storage engineer, and I still have nightmares of the transition from U160 to U320 SCSI. I remember working long hours in a lab with sets of presumably commodity SCSI hard drives, each creating a unique interaction on the SCSI bus. Drives from vendor A would work fine. Drives from vendor B would work fine. However, if drives from vendor A and B were together, the entire system would break. The results would vary based on controller firmware, drive manufacturers and drive firmware revisions. After months of detailed engineering and test analysis, we would be able to release a qualified and validated system that worked.
Times and technologies have changed to some extent, and some may argue that drive standards have improved. But I would argue that new hardware technologies, such as solid state, are evolving every day. The bottom line is that if we extend the idea of storage software abstraction to its fullest, it should be able to work with any hardware. If we see that as truly desirable for SDS deployments, the number of possible technology combinations in a system over the life of the software could become endless. In this scenario, the responsibility -- and cost -- to validate and integrate new hardware technologies will fall primarily to IT.
Organizations that are evaluating SDS products today often recognize this challenge and ask for hardware options that have been qualified as a way to help mitigate the risk. Many SDS offerings also have an appliance option to ease the integration concern. However, some might argue that this isn't truly software-defined storage. Additionally, SDS products that target large content repository storage workloads, such as object storage, create multiple copies of data or use erasure coding to improve resiliency, reducing the risk of data loss if a non-validated hardware component is deployed.
I expect some organizations to welcome the opportunity to deploy storage technology as software. These organizations may be large enough to support their own qualification efforts and procure enough hardware where the scale could justify the implementation of non-vendor qualified components. For these deployments, SDS technology as a software-only deployment may make tremendous sense.
Organizations will have to make a choice based on what is best for their business. As noted, SDS players are recognizing this challenge and responding by delivering appliances or providing lists of certified components. When choosing an SDS product, it is critical to evaluate if the vendor can truly offer the benefits of SDS -- whether it is delivered as software or as hardware.
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