IBM’s recent storage announcement covered a number of new and enhanced solutions across IBM’s Storage software and Storage systems portfolio, but for simplicity’s sake, my focus today is the significant support the company is throwing behind the revolution inspired by NVMe (nonvolatile memory express
Note that the business storage market has changed dramatically in recent years with revolutions sparked by software-defined storage technologies and flash-based storage hardware, in both of which IBM has been a leader. To those two we can now add a storage connectivity revolution or NVMe. Although this revolution could be considered separate, the primary benefit is to increase the performance of flash storage (not hard disk storage). Therefore, it can also be considered a subset of the flash storage revolution.
As it has demonstrated in past such events, IBM has a well-articulated strategy that includes necessary planning and R&D investments to deliver NVMe as a part of its storage environment in a reasonable, achievable time frame. However, before we see what the company is doing we need to understand the technology and why it is important.
The Basics of NVMe and NVMe-oF
NVMe is a logical device interface specification for accessing nonvolatile storage media. It has been designed to exploit the low latency and internal parallelism inherent in solid state devices (SSDs), not hard disk drives (HDDs) due to problems inherent in spinning devices, such as rotational latency.
In SSD- and flash-based storage environments, NVMe replaces SCSI (Small Computer System Interface) at both the device and network level. Unlike SCSI, which is limited to a single queue, NVMe enables massive parallelism for I/O to a connected device, which is a boon for flash storage that can take advantage of these changes.
The technology is also remarkably flexible. NVMe over Fabrics (NVMe-oF) maps the NVMe protocol across a network between a host and a storage array. The fabrics supported include Fibre Channel, Ethernet, and InfiniBand. NVMe-oF uses remote direct memory access to reduce the overhead of data handling as compared to existing methods.
Although a remote connection is never as fast as any direct-connected device, the goal is to add no more than 10 µs of latency. The especially good news is that the overall result is very low overhead, very low latency, and high throughput I/O over a data center fabric as compared to alternatives.
The NVMe revolution is not an overnight coup d’état but rather a progressive one that will take a while to achieve. Progress (and solid results) can be manifested, tracked and evaluated in a step-by-step manner, much like the flash storage revolution itself. And that is what IBM is focusing on delivering to its customers.
First fruit of NVMe-oF is the FlashSystem 900
The IBM FlashSystem 900 is fully enabled (i.e., both hardware and software) to support NVMe-oF for InfiniBand. Using this as the first IBM flash storage system that takes advantage of NVMe-oF makes good sense. Why so?
- First, although performance is important for all-flash storage, the FlashSystem 900 is the Kentucky Derby horse in the IBM stable of all-flash systems. Its target applications are those that require extreme performance acceleration.
- Secondly, the FlashSystem 900 applications do not require data services, such as thin provisioning, snapshots and data copying, which add overhead to the extreme performance and require software development on the part of IBM to support in an NVMe-oF world. That work is still ongoing.
Now, IT organizations will have to make an investment to gain the benefits of this solution. It requires two dual port NVMe-oF 100 Gb Mellanox adapters at the host, an updated device driver in the operating system distribution that supports the NVMe protocol, a Mellanox Switch IB2 SB7800 in the network, and a FlashSystem 900 with the proper 40Gb QDR InfiniBand ports connected. That seems a reasonable investment to obtain the extra performance.
Newly purchased storage systems supported by IBM’s Spectrum Virtualize and IBM’s Spectrum Accelerate software are now hardware enabled, but the version of software that supports NVMe-oF is not yet available. This means that when the software is available, all that has to be done to those storage systems is to have the latest version of Spectrum Virtualize or Spectrum Accelerate software installed. Since most customers have a software maintenance contract, the eventual software upgrade will come at no charge.
Spectrum Virtualize-supported systems — namely the FlashSystem V9000, the Storwize V7000F and V7000, and the SAN Volume Controller — are now NVMe over Ethernet and Fibre Channel-ready. The Spectrum Accelerate-supported FlashSystem A9000/A9000R are now NVMe over Fibre Channel-ready. All this is part of what IBM stresses is an ongoing commitment to NVMe, while also continuing to protect its customers’ legacy storage investments.
Mesabi musings
The world of enterprise storage continues to change dramatically and the promise of NVMe to revolutionize storage connectivity is simply the latest trend. The first area to be addressed in detail by IBM is in its FlashSystem 900’s NVMe over InfiniBand capability.
This will demonstrate the commercial and business validity of NVMe-oF in highly visible, high-performance environments. IBM has also announced that its all-flash products that are supported by either Spectrum Virtualize or Spectrum Accelerate are hardware-ready for NVMe so that they simply have to wait for the software upgrades to become available. Overall, IBM customers should be happy that the company is committed to leading this newest storage revolution.