Meet the Needs of Data-intensive Applications and Hyper scale Computing
Modern data centers require solutions that offer maximum performance with minimal latency and minimal power consumption. While compute and storage devices have native Peripheral Component Interconnect Express (PCIe) for internal communication, they all use different technologies, such as Ethernet or InfiniBand, to connect externally. The PCIe was used as the backbone of the computer industry, especially the storage systems. The PCIe software model allowed existing applications to be used seamlessly, while offering scalability and a significant performance improvement with a smaller board footprint. The latest specification release of the PCI Special Interest Group (PCI-SIG), the PCIe Gen5 adds value to the enterprises and data centers to expand the boundaries of interconnect in electrical before they can move to optical domain. The PCIe Gen5 talks about achieving the double the data rate of PCIe Gen4 PCIe-based Flash memory designs are the industries latest cynosure and the lion’s share of today’s data center storage remains in HDD designs where cost plays a major role. SSDs costs are rapidly going down and closing cost/GB gap between SSDs and HDDs but most observers believe that the two technologies will continue to co-exist for a while.
Today, PCIe is used throughout mainstream storage products to:
- Aggregate storage devices
- Connect the communication subsystems to the storage subsystems
- Offer mid-plane or backplane pathways for storage appliances and storage servers
- Enable failover, redundancy, and mirroring of storage systems
Hybrid Storage Systems
Although SSDs offer higher performance than spinning media, they are more expensive, and are expected to remain so for the foreseeable future. But it turns out that systems can be built out of a large amount of HDD storage, and a relatively smaller amount of SSD memory, but achieve similar performance to an all-SSD system at a much lower cost. These hybrid systems are now being offered by many storage system vendors, and these, too, will likely proliferate. PCIe switches play a key role in these designs.
Non-Volatile Memory Express (NVMe) Interface
In recent times, the laptops and workstations have been reported to be faster and more efficient. It is not the CPUs and GPUs making it. It is the memory !
The NVMe-SSD based Memory.
The Non-Volatile Memory Express (NVMe) interface is based on PCI Express. It is becoming the preferred way to access flash memory because it has less overhead than conventional disk interfaces like SATA. The datarates offered by the various data memory transfer approaches are HDD = 200MBps, SATA SSD = 550MBps and NVMe SSD = 3GBps. NVMe is latency optimized and its performance can scale because of PCI’s multilane approach. The variants available are x2 PCIe NVMe and x4 PCIe NVMe among others.
NVMe is also the foundation of the Thunderbolt interface, which is paying dividends with external graphics cards for gaming, video editing and Full-HD Video streaming, as well as external data storage.
HDD = 200MBps, SATA SSD = 550MBps, NVMe SSD = 3GBps
The Future: Fabric based Storage Systems
The use of PCIe in storage - at every level - has sufficient benefit and momentum that it appears inevitable, and most industry observers have predicted a rapid increase in its use. But there is an equally exciting opportunity for PCIe-based storage as the data center opens its eyes to innovative architectures. If your fabric is based on PCIe, then adding PCIe-based SSD (or HDD) storage becomes as easy as plugging in a blade with arrays of storage, all providing a direct connection to the underlying memory technology with the lowest possible latency and complication.
About the author
Dr G S Javed is the Lead - High Speed Circuits group in Terminus Circuits where he works on high speed interface IP development for protocols like PCIe, USB and MIPI. He has also founded King Consultants-Education where he coaches Masters and PhD students on Research Methodology and Technical Writing. He inculcates experiential learning and innovation in his Design Thinking course. He enjoys travelling and meeting people.