Software-defined storage (SDS) does not separate storage from the hardware; it abstracts storage resources from it. It is a software controller that virtualizes and manages your physical storage resources, sitting between the physical storage and data requests and controlling how and where data is stored. SDS consolidates all storage capacity and creates a unified, centrally managed storage pool that provides access services, networking, and connectivity for all your applications, without making assumptions about the underlying hardware’s capabilities. And because it operates through an abstraction layer, a control plane, it can dynamically pool storage resources via policy-based management and automated provisioning.
The SDS model has gained prominence and adoption due to its inherent flexibility. Its hardware independence eliminates reliance on proprietary infrastructure, allowing you to choose any hardware vendor that meets your needs and avoiding vendor lock-in. It’s an attractive architecture model because it maximizes storage capabilities while minimizing administrative overhead by automating and orchestrating storage management across private or public clouds. With this model, storage can be scaled up or out with minimal disruption to operations and reduced capital investment.
Software-Defined Storage Architecture
SDS is architected to abstract storage resources from physical hardware, creating a flexible, scalable, and centrally managed storage environment. Each core architecture component would be present in the implementation across various software-defined storage solution vendors. Here is a list of key components of software-defined storage architecture:
Abstraction Layer: The core component that decouples the storage services from the physical hardware itself and makes virtual storage pools appear as a single storage pool to applications and users.
Control Plane: The centralized management layer for storage operations, ensuring efficient resource utilization by orchestrating and automating storage tasks: provisioning, monitoring, policy enforcement, and metadata.
Data Plane: The layer that manages actual data storage and retrieval by executing read/write operations and essential data services (replication, deduplication, compression). It ensures data integrity and high performance during data access.
Management Interface: A tool used to interact with the SDS system to gain visibility and control over the storage infrastructure; in most cases, it provides a dashboard for configuring, monitoring, and managing storage resources and simplifies administrative tasks.
What do you need to run software-defined storage?
The SDS model is an effective solution for modern data storage needs. [Refer to A Comprehensive Guide to Enterprise Software-Defined Storage Technology]. With these components and considerations, you can effectively deploy and manage an SDS environment, benefiting from its flexibility, scalability, and cost efficiency.
- Storage Nodes: physical or virtual servers that contribute storage resources. Each node runs on the SDS software, which abstracts storage resources and aggregates them into a centralized pool. These can be commodity or proprietary servers, as long as there is adequate CPU, memory, and storage capacity. Software-defined storage vendor solutions will vary depending on the storage media implemented, which can include SSDs, HDDs, or NVMe drives. You should implement a solution that meets the performance and capacity requirements of your applications.
- Network Fabric: The high-speed, low-latency Network Interface Cards (NICs) and network technologies that connect, facilitate node communication, and ensure data can be transferred efficiently across the cluster. When choosing a networking option, consider your applications’ performance and latency requirements. Networking technology options include iSCSI, Fibre Channel, InfiniBand, NFS, and NVMe over TCP.
- While SDS is traditionally associated with networked storage solutions such as NAS and SAN, it can also be implemented in a Direct Attached Storage (DAS) architecture. In a DAS implementation, the storage devices are directly connected to a single computer or server without a network in between.
- Cluster Management: Aggregating storage resources by clustering the storage nodes and managing them as a single entity has many technological and operational advantages, such as high availability, redundancy, scalability, and simplified administration. If one node fails, others can take over its workload to maintain continuous service. The DAS model is not a clustered architecture.
- SDS Software: Finally, there’s the SDS layer running on each storage node, managing the storage abstraction, resource pooling, policy enforcement, and data services.
Continue your learning: The Ultimate Software-Defined Storage Glossary
How Do SDN and Software-Defined Storage Work Together?
Think of Software-Defined Networking (SDN) and Software-Defined Storage (SDS) as the “brain” and “muscle” of a modern data center. While they manage different resources, they work together to create a Software-Defined Data Center (SDDC), in which hardware is a generic pool of resources controlled by a central software layer.
SDN and SDS Comparison at a Glance
| Feature | Software-Defined Storage (SDS) | Software-Defined Networking (SDN) |
|---|---|---|
| Primary Goal | Abstract storage hardware from data management. Manages where data lives and how it’s protected. | Abstract network hardware from traffic routing. Manages the flow of data packets across the network. |
| Resources Pooled | HDDs, SSDs, NVMe | Switches, Routers, Firewalls |
| Role in the Software-Defined Data Center | Requests specific data paths and speeds. | Provisions and secures data paths dynamically. |
Here is how they integrate to make life easier for platform architects:
- Unified Control Plane: In a traditional setup, if you add a new storage array, you have to manually configure the network switches to allow traffic to reach it. With SDDC, the Control Plane handles this automatically. When the SDS layer creates a new virtual disk, it can signal the SDN controller to automatically provision the necessary bandwidth and lanes to ensure that data can move without hitting a bottleneck.
- Quality of Service (QoS): If a high-priority database on your SDS needs to sync for backup, the SDS layer signals the SDN that it is a Tier-1 operation. The SDN then prioritizes those storage packets over less important traffic, ensuring storage performance remains consistent.
- Policy-Based Automation: Instead of configuring individual nodes, you define policies across the cluster. Because both are software-defined, these policies are linked. For example, if you move a VM from Server A to Server B, the SDS moves the data access point, and the SDN automatically reroutes the network path to follow that VM.
