Organizations that need to accommodate the huge surge in data growth, and do so at an affordable price, are turning to SDS. As a result, IDC forecasts the worldwide software-defined storage (SDS) market will see a compound annual growth rate of 13.5 percent over the 2017-2021 forecast period, with revenues of nearly $16.2 billion in 2021. However, as adoption of SDS grows, it is important for organizations to be knowledgeable about current options.
The SDS market is still in a “wild and woolly” phase in which there is no set of uniform standards. Potential issues include compatibility problems, inconsistency issues and a lack of features. Any one of these, let alone a combination of them, can create problems. Below are recommendations for what to avoid and what to look for so that you can deploy an SDS strategy that best serves your organization’s needs.
Is the Storage Really Unified?
You are likely to maximize your solution with a unified SDS system that brings all the “flavors” of storage together. For instance, if your current file-based storage system offers support for object store as well, it can save you the hassle of managing and balancing many different complementary storage systems. First, this unified approach is easier to manage, and second, it makes better and more efficient use of resources in relation to performance and capacity. It’s similar to virtualization, where you cut back on hardware resources that are idling. By using a unified approach, you are using your storage resources more intelligently.
The trick is to be aware that some software-defined storage companies claim to offer flexibility and the ability to meet enterprise needs with object, block and file storage, be both hyper-converged and hyperscale, and claim to support flash storage. However, many lack the features to back up those claims.
When looking at SDS options, it’s important to know that many of them are narrow in scope. They often focus on one use case, such as:
- Scale-out file systems
- Object storage
- Hybrid cloud
Solutions like this that are narrowly focused can offer an appealing price tag – typically about one-third the price of more comprehensive options. But you get what you pay for; they also have one-third of the features. In addition, they are not focused on general-purpose NAS.
Why It’s Critical to be Consistent
The majority of organizations would benefit from a general-purpose NAS that scales well. But just as with SDS, not all NAS options are created equal.
A critical factor in scale-out NAS, and one that often is not well understood, is consistency. Some storage environments are only eventually consistent. This means files written to one node are not immediately accessible from other nodes. Even when the other nodes have been updated to record the change made to the original node, a delay of just fractions of a second can cause problems with accessing applications or users. This can be caused by not having a proper implementation of the protocols or insufficient integration with the virtual file system.
Fortunately, this is not the only option. Rather than being eventually consistent, being strictly consistent means files are accessible from all nodes at the same time. The view of the file system through each node is strictly consistent, so that any modification on one node is instantly available from any other node. Make sure that your solution can be consistent between protocols as well. That means if you write something in SMB, for example, it should be immediately visible over NFS as well.
What an All-Inclusive SDS Approach Looks Like
A comprehensive SDS approach, along with strictly consistent NAS and a unified architecture, looks like this:
- Hyperconverged – Software-based architecture integrates compute, storage, networking and virtualization resources and other technologies on a commodity server.
- Not tied to hardware – You can use standard commodity storage hardware and servers by avoiding lock-in to a specific vendor and/or technology. You can add additional hardware of your choice as needed to scale performance and capacity over time.
- File systems – File storage is a must for managing unstructured data. Make sure your SDS setup includes crucial file features such as tiering, quota, snapshot, encryption, antivirus, WORM and retention. It should also be able to integrate into Microsoft Active Directory, have support for multiple authentication providers and enforce authorization checks. If your company is a large one, ensure that the architecture has support for multi-tenancy, where you can create multiple file systems in the same environment.
- Hybrid cloud – When you have a local presence and a presence in the cloud, part of your data needs to live in and be accessed from the cloud as well. For example, part of your local storage system will be exposed to virtual machines running in a public cloud like Amazon. That means your SDS file system needs to cover both environments so you can easily pass files between them.
- Disaster recovery – If you choose an SDS option with a storage cluster that is important to back up, you can protect each of your applications with a unique disaster recovery policy and remain highly available.
- Scalable and flexible – You can start small, then rapidly add multiple virtual machines to the same cluster if you use SDS. This eliminates the cost and hassle of building new clusters in order to accommodate scale-out. If a storage cluster is built on a symmetric architecture, linear scaling up to hundreds of petabytes and billions of files is possible simply by adding more storage nodes to the cluster. Adding storage nodes and increasing capacity can be carried out during runtime and does not interrupt any ongoing operations in the cluster.
Making the Best Decision
Organizations are embracing SDS for its rapid scalability and appealing price, but caution is advised. What SDS providers claim and what they actually offer are not always in sync; watch out for options that have specific use cases and limited feature sets. Instead, look for an SDS architecture that is both compatible and consistent and uses general-purpose NAS. Storage is an important investment, so use the recommendations above as a guide to avoid buyer’s remorse.
For an in-depth analysis of the strategies and technologies that leading businesses are embracing in order to boost speed, increase reliability, and see a major ROI for their storage infrastructures, check out this research report by Aberdeen’s Jim Rapoza.
Stefan Bernbo is the founder and CEO of Compuverde.