Software-Defined Storage: What Can It Do for You?
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SOFTWARE-DEFINED STORAGE: WHAT CAN IT DO FOR YOU? Mikhail Gloukhovtsev Senior Cloud Solutions Architect Orange Business Services Table of Contents 1. Introduction ......................................................................................................................... 3 2. Definition of Software-defined Storage ................................................................................ 5 3. Why Has the SDS Concept Emerged? ................................................................................ 7 4. The Main Capabilities of SDS and What Value They Provide to Customers .......................10 5. Does Every Company Need SDS?.....................................................................................14 6. Co-existence of Traditional Storage Platforms and SDS ....................................................14 7. SDS Relies on Hardware Innovations ................................................................................15 8. Hardware Support Is a Must-Have Even for SDS ...............................................................16 9. SDS Vendors, Products, and Solutions ..............................................................................16 9.1 What Features to Consider While Selecting an SDS Vendor and Product .......................17 9.2 A Variety of SDS Platforms ..............................................................................................18 9.3 EMC ViPR .......................................................................................................................18 9.4 EMC ECS Appliance .......................................................................................................23 9.5 EMC ScaleIO ...................................................................................................................24 9.5 EVP: Federation Software-defined Data Center...............................................................27 9.6 VMware VSAN.................................................................................................................30 9.7 VMware ECO:Rail ...........................................................................................................33 10. Conclusion .....................................................................................................................35 11. References .....................................................................................................................36 Disclaimer: The views, processes, or methodologies published in this article are those of the author. They do not necessarily reflect the views, processes or methodologies of EMC Corporation or Orange Business Services (my employer). 2015 EMC Proven Professional Knowledge Sharing 2 1. Introduction When I first heard about software-defined storage (SDS) at a technical conference two years ago, I got confused - software has always defined a properly designed infrastructure, has it not? For example, redundant array of independent disk (RAID) sets, well known for more than 30 years, can be seen as software-defined storage. Is “software-defined storage” part of what is covered by a marketing phrase – “Software-defined Everything”1 – that has been called the "next big thing"? How can “software-defined storage” be defined as an IT term to prevent misusing it in a chain of “software-defined X” constructs like “software-defined radio”2? Furthermore, for many years some storage vendors claimed the advantage of their “hardware- based performance” products and it appeared to make sense. While I understood that new software releases come much more frequently than new application-specific integrated circuit (ASIC) types, should it be seen as the main benefit of software-defined storage? Christos Karamanolis (VMware, Office of the CTO) wrote that 2012 was the year of “software- defined data center.”3 It was the year when the term “software-defined data center (SDDC)” was coined by VMware’s former chief technology officer (CTO), Dr. Steve Herrod. The following years have shown that we witness the emergence of the new concept of data center defined by various terms – software-defined data center (SDDC, VMware),3,4 application-centric infrastructure (ACI, Cisco),5 software-defined environment (SDE, IBM),6 software-defined infrastructure (SDI, Intel),7 federated software-defined data center (EMC, VMware, Pivotal – EVP).8 SDS can follow the development and acceptance of “software-defined networking” (SDN) that has gained popularity as a component of the SDDC. We see the SDS buzzword in many online and print trade magazines and hear it at almost every technical briefing on the next generation data center. Is SDS really the next big thing in storage technology? Or is it just hype generated by the marketing machine as Rich Castanga, the editor of Storage Magazine,9 and other critics of SDS point out? Valdis Filks, research director for Storage Technologies and Strategies at Gartner Research, ironically discussed whether SDS is, in fact, the re-labeled storage resource management, a kind of SRM 2.0 – a creature of “surreally defined marketing.”10 If SDDC as an umbrella term for all the derivatives mentioned above (ACI, SDE, SDI, and EVP) is a semantic construct, SDS as an SDDC component is considered by SDS critics as “a synonym for private storage clouds, which is a synonym for Storage as a Service, which is a synonym for managed storage.”10 Critics of the view of SDS as a complete replacement of 2015 EMC Proven Professional Knowledge Sharing 3 hardware-centric storage remind that SDS relies on continuing progress in storage hardware development.9 Indeed, innovations in hardware technologies such as new powerful processors from Intel and flash storage are enablers for SDS. This article is my attempt to find answers to the questions of what SDS is and how we can separate marketing myths and reality. I review the benefits of SDS, challenges in developing this technology, how SDS is related to the broader concept of SDDC, and SDS use cases. How will various non-IT companies include SDS in the storage services roadmaps they develop to meet business requirements? As large investments have been made in the existing storage environments, it is important to understand whether traditional storage platforms can coexist with SDS. Or will legacy storage be converted into SDS? To answer these questions, we need to understand first how SDS is defined. 2015 EMC Proven Professional Knowledge Sharing 4 2. Definition of Software-defined Storage Storage vendors offer various definitions of software-defined storage (SDS) but there is no generally accepted definition at this time. The common element in all the definitions is "hardware independence," as hardware-agnostic storage solutions allow users to deploy storage on hardware they choose, including commodity hardware, and thereby avoid vendor lock-in for their future storage purchases. In the “Software-defined Storage” Working Draft,11 the Storage Networking Industry Association (SNIA) proposes an SDS definition via attributes and functionality rather than giving a brief definition. In my opinion, this definition has been chosen with the goal of making such a definition applicable to the broad trends in SDS development. Actually the SNIA Working Draft considers SDS implementation model as the main differentiator of SDS: “Data Services can be executed either in servers, storage, or both spanning the historical boundaries of where they execute.”11 They can run on any storage device and support many different data types and access protocols. Gartner defines SDS as “an architectural vision that includes the principles of orchestration, instrumentation and automation. [It] can be fully realized only by a standards-driven integration of heterogeneous storage hardware and software platforms.”12 Other definitions of SDS focus on separation of data and control planes: “SDS layers a control plane for applications and policy on top of a data plane, which essentially manages information across various forms of infrastructure from on premise to the cloud.”13 Or they underscore the hardware-agnostic feature of SDS: “SDS is any storage software stack that can be installed on any commodity resources (x86 hardware, hypervisors, or cloud) and/or off-the-shelf computing hardware.”14 The control plane becomes a centralized storage resource management (SRM) service capable of managing pools of heterogeneous resources across the entire data center. VMware’s definition of SDS is VM-centric: “Software-defined Storage (SDS) is the vision that storage services are dynamically created and delivered per VM and controlled by policy.”15 The VMware vision of SDS assumes the transition of storage services from hardware-centric arrays to VM-centric environment. This will lead to alignment of the storage services with application requirements. 2015 EMC Proven Professional Knowledge Sharing 5 The SNIA concept of SDS emphasizes platform independence of SDS, allowing customers to use commodity hardware. At the same time, it considers the possibility of integration of traditional storage and SDS when SDS may be an addition to the existing storage platform by providing new features or an enhancement to the existing functions of specialized hardware. Figure 1: The SNIA Vision of Software-defined Storage (Ref. 11) According to the SNIA Working Draft,11 other attributes of SDS are scale-out capability, use of storage resource pools, ability for incremental growth, management automation, self-service interface for