An Introduction to Composable Disaggregated Infrastructure

What is composable infrastructure?

Composable disaggregated infrastructure (CDI) is an approach to designing and managing IT/ICT resources in which compute, storage and networking resources are treated as services. Systems are composed as required, and when the composed system's work is complete the resources can be returned. This infrastructure is highly flexible and modular, allowing resources to be allocated and reallocated dynamically based on the needs of applications or workloads. The main goal is to improve efficiency, scalability and agility in managing data center resources.

What are the key characteristics of CDI?

Key characteristics of composable infrastructure include:

• Resource pools: Compute, storage and network resources are pooled together and can be dynamically allocated based on demand. This means resources can be quickly repurposed without the need for physical changes to the infrastructure.
• Software-defined: The infrastructure is managed through software, often using APIs and management tools. This software layer allows administrators to easily configure and control resources programmatically.
• Automation: Automation tools are heavily used to orchestrate and manage the allocation and deallocation of resources. This reduces manual intervention and speeds up the deployment of applications and services.
• Scalability: Composable infrastructure can easily scale up or down based on the requirements of workloads, providing a more efficient use of resources and better cost management.
• Agility: By decoupling hardware resources from specific uses, composable infrastructure provides greater flexibility in responding to changing business needs, application demands or workload requirements.

Who are the key technology players in CDI?

The leading CDI technology vendors are Liqid and GigaIO. These two solutions predate the work of Compute Express Link (CXL) which has broad industry backing.  Liqid, GigaIO and CXL each offer unique capabilities as platforms for composable infrastructure.

Liqid's CDI solution allows for the creation of dynamically configurable, ideally sized, bare-metal servers. It reduces deployment time from weeks to minutes and its non-proprietary nature enables the use of elements from an array of ecosystem partners, avoiding vendor lock-in. Liqid's CDI solution also integrates with Intel technology and Dell servers and blades, offering various composable offerings. Liqid's CDI Lab showcases how to create impossible hardware configurations that are unfeasible in the physical world, allowing administrators to compose bare metal servers with any number of configurations via software.

GigaIO's Rack-Scale Composable Infrastructure operates over the RedFish API, which is entirely agnostic, enabling users to run their choice of new or existing servers, storage, accelerators and so forth. It offers the industry's lowest latency and highest bandwidth, and its end-to-end PCIe with Trusted Platform Module (TPM) on the switch virtually eliminates the potential for undetected attacks. GigaIO's solution can also reduce TCO by up to 50 percent as users can easily share costly resources across multiple servers to achieve maximum utilization and prevent over-provisioning.

CXL (Compute Express Link) leverages the PCIe 5.0 physical layer infrastructure to create a common memory space across the host and all devices in a vendor-independent manner, even those outside the chassis. This new interconnect capacity will complement and enable composable disaggregated infrastructures (CDI) solutions such as Liqid and GigaIO and leverage resources located outside the confines of a server chassis. CXL-enabled systems also will provide the framework for today's most efficient and performant solutions that are designed to support complex workflows such as HPC and AI/ML, even assessing and improving operations in real time.

How will CDI affect data centers?

CDI is a fundamentally different architecture from non-composable, non-disaggregated systems and will impact data centers. It is a high-performance architecture (HPA) that will draw large amounts of power. Moreover, the limited interconnect distance will drive CDI systems to be highly dense. Finally, CDI requires a rack-scale deployment strategy. 

Thus, CDI systems will require the delivery of high wattage to racks that will be generating a great deal of heat. The data center will need to support high-density racks, which will likely require changes to power distribution and the introduction of advanced cooling such as rear door heat exchangers and direct-to-chip liquid cooling. 

Is there an economic driver for CDI?

CDI is an engineering solution that addresses some key business use cases and even enables some use cases that would otherwise be impossible to achieve. However, in addition to the technical and business enablement drivers, there may be significant economic reasons to adopt CDI.

By decoupling the hardware that makes up the overall system, it is possible to treat them as separate economic units.

• Drive higher utilization, expensive components such as GPUs and TPUs become obsolete very quickly. To achieve maximum value from the capital invested the utilization of those components needs to be maximized.
• Refresh cycle mismatch, quickly obsolete components such as GPUs, can refreshed independently of the rest of the systems.
• Comparatively lower ESG footprint. Highly dense, high utilization systems carefully powered and cooled have a better carbon footprint than an equivalently capable number of traditional systems.

What is the future for CDI?

Liqid and GigaIO enjoy a first-mover advantage in CDI architectures as both systems are proprietary and do not interconnect with each other. However, the industry is responding with a standards-based approach in CXL. The definition and implementation of standards take longer than a non-standard approach, but as has been seen before, ultimately lead to wider spread adoption. 

Interconnect vs. orchestration

At a minimum, CDI requires that the components of a system have an interconnect mechanism; but that does not solve the use cases that CDI is addressing. Those components need management software, known as "orchestration," which allows the user to operate the environment. Both Liqid and GigaIO have interconnect technologies as well as orchestration software. CXL is expected to standardize the interconnect layer of the system and both Liqid and GigaIO, if they adapt to that layer, will have a key role in the market.

Liqid and Gigabyte (GigaIO) provide full-fledged composable infrastructure solutions that offer flexibility, scalability and dynamic resource management. In contrast, CXL is a high-performance interconnect standard that enhances communication and memory sharing between components, which can complement composable infrastructure solutions by improving the efficiency of resource utilization.

Potential scenarios

1. Integration and enhancement:
   1. Proprietary systems: Integrate CXL to enhance their existing solutions, offering improved performance and interoperability while maintaining their unique value propositions.
   2. CXL: Provides the underlying technology that enables better resource sharing and performance, becoming a foundational component within the broader composable infrastructure ecosystem.
2. Coexistence:
   1. CXL and proprietary systems: Coexist in the market, with CXL enhancing the performance and efficiency of proprietary systems while these systems continue to provide comprehensive resource management and orchestration solutions.
3. Industry evolution:
   1. As the industry evolves, proprietary systems may increasingly adopt open standards like CXL, leading to greater interoperability and performance while still offering unique, differentiated features that meet specific customer needs.

While CXL offers significant benefits in terms of performance and interoperability, it is not likely to completely displace proprietary systems such as Liqid and GigaIO. Instead, CXL will enhance these systems, enabling them to offer even more powerful and flexible solutions. Proprietary systems will continue to provide value through their comprehensive software platforms, customization, and specialized capabilities. The future landscape will likely see a harmonious integration of CXL with proprietary solutions, driving the evolution of composable infrastructure.