Software-defined storage promises enterprises much greater flexibility and freedom of choice when it comes to their data storage deployments.
By taking lower-level software operations and day-to-day software management, and abstracting them from hardware, customers can run their storage on commodity servers and expansion shelves.
That, at least, is the theory. However, the market for software-defined storage is complex, with a range of options to take into account.
In this article – a follow-up to the first, which looked at software-defined storage pros and cons – we look at some of the software-defined storage offerings on the market, which range from those provided by the big hardware players, through the software-defined storage specialists, to cloud, virtualisation and container-focused offers.
Unsurprisingly, the big enterprise storage providers have all embraced software-defined storage, although their approaches differ.
IBM, for example, offers its Spectrum Storage Suite for software-defined storage. This includes management tools – IBM Spectrum Control – archiving and object storage, plus Spectrum Accelerate, which provides software-defined block storage.
Hitachi Vantara provides its Hitachi Virtual Storage Software, which operates on-premise, in the cloud, and as a hybrid capability with hyper-converged infrastructure. The supplier also provides a plugin for Kubernetes-based container clusters.
HPE stated that its software-defined storage supports VMWare, Microsoft Hyper-V and Linux KVM. The supplier positions software-defined storage as part of its Synergy software-defined infrastructure offering. Software-defined storage is also offered with HPE’s hyper-converged hardware appliances.
Dell Technologies has one of the broadest software-defined storage offerings of the main IT systems suppliers, with different packages aimed at specific use cases.
VxRail, for example, is not strictly software-defined storage, but rather a hyperconverged infrastructure platform for enterprises that run VMWare. The supplier also offers UnityVSA, a software-defined storage alternative to its Unity hardware. Dell also offers a scale-out software-defined NAS system (IsilonSD Edge), and ECS, a software-defined object storage technology.
Most software-defined storage suppliers offer at least one preferred appliance or hardware option. There are, though, some companies that only offer software.
Among the pure-play software-defined storage suppliers, DataCore is one of the most focused. It provides two products, VFilO for file and object storage, including the ability to create a single unified namespace, and SANsymphony, which uses industry-standard hardware to provide block storage.
The software-only market does, however, include two significant players: Microsoft and VMWare. Although neither supply their own hardware, they have myriad partnerships with hardware providers. And of course, many IT managers are likely to use these suppliers’ software-defined storage as part of wider virtualisation deployments.
VMWare’s vSAN works with its VSphere software to provide a range of advanced features, including erasure coding and support for storage APIs in Kubernetes.
Microsoft provides Storage Spaces Direct as part of Windows Server (going back to the 2016 edition) and as part of Azure Stack HCI. The system will run on as few as two servers.
One further software-only option is open source. Perhaps the best-known open source software-defined storage is Ceph. Historically, Red Hat has been Ceph’s largest contributor, and it continues to provide an enterprise edition of Ceph, even though Red Hat’s storage division is now part of IBM’s.
Scale-out NAS software-defined storage
Network-attached storage is a key use case where businesses need to add capacity via scale-out growth. As data volumes increase, the ability to add arrays or nodes without replacing existing equipment is very valuable.
NetApp remains one of the most established NAS suppliers. NetApp’s OnTap software is a data management application that works with standard x86 hardware and NetApp’s own offerings, as well as cloud storage. OnTap can scale to 176 petabytes for object storage workloads.
Cloud-optimised software-defined storage
Almost all software-defined storage suppliers claim a degree of cloud compatibility, ranging from complete integration of cloud, hybrid and on-premise volumes into a single namespace, to relatively simple cloud add-ons, such as backup and archiving. Indeed, part of the point of software-defined storage is to break free of hardware constraints and to use the same set of tools across environments.
That said, suppliers such as Nutanix, with its Unified Storage, targets on-premise and cloud environments, including multi-cloud setups. Although the supplier does also provide its technology on appliances, it is often viewed as a cloud-first offering, supported by features such as strong support for Rest APIs.
Object storage software
Adoption of object storage has been driven by the cloud hyperscalers, but the technology is now available for enterprises to use on-premise, for their own cloud setups and in hybrid environments.
Scality, for example, offers scale-out file and object storage through Ring, which supports AWS-compatible APIs and standard NFS and SMB interfaces. Ring is a software-only product, and although it started out as an object storage platform, it also competes in the scale-out NAS market with file system support.
Containerised software-defined storage and SDS for containers
With the growing importance of Kubernetes and other container-based environments in enterprise IT, firms are looking at tools that will support storage for containers. Meanwhile, some suppliers are “containerising” their storage or data services to make them easier to deploy, which is also known as container-attached storage.
IBM offers container-native storage access as part of Spectrum Scale, while its Storage Suite for IBM Cloud Paks provides storage management to container environments.
Pure Storage supports containers through its Portworx platform. Portworks started out as a way to provide persistent data storage and data protection to containers, which are usually stateless.
However, Portworx Data Services now support a wider range of container environments and databases on a consumption-based model through Portworx Enterprise. This allows those applications to access storage when they need it.