The NVMe Revolution

I hope everyone is staying safe and well in these unusual times (COVID-19 year 2 if reading this in the future!).

As some of you may know, one of my hobbies is writing EDM style music, having built up a synth and drum machine collection over many years. During the lockdowns and force travel restrictions I’ve recently got into actually building synths and drum machines. From clones of Roland’s 303 and 909 to full six voice synth modules (Mutable Ambika).

So what has this got to do with NVMe you may be wondering. Well one of the things I’ve learned is that there are many small 8 or 32-bit microprocessors that run all these DIY synths and they all need some firmware, bootloaders etc to be able to do anything. There are many different models, Atmega, Arm, ST etc, and so you end up having to buy a whole load of ICP (in circuit programming) programmers. One for each type of processor. My daily workhorse is a MacBook, but some of these older programmers, especially when programming 27Cxxx old school EPROMs from the 1980’s, will only run with software on Windows.

I had to resurrect my old PC (which my son had stolen lots of parts from) and to cut a very long story short, I ended up building a brand new PC over the holiday season. Being a storage guy, and realising the motherboard I had bought has a pair of M.2 PCIe Gen4 x4 storage ports, only the best would do.

I went for a well known (they make phones) brand with full Gen4 support and boy, what a difference. My old PC had some 7.2K spinners, noisy, and very slow by comparison. The benchmarks on this new machine are giving close to 4 GB/s from the boot device, and now even Windows has a fast boot time! Comparing with my old PC at maybe 20-25MB/s and even with an old SATA SSD at around 150MB/s – the difference is enormous!

The same goes for PCIe attached NVMe enterprise flash and Storage Class Memory (SCM) drives, of course you all should know about our industry unique FlashCore Modules (if not, look back at my older posts) which include zero impact data reduction in the form of 100% hardware path compression and encryption built in. My measly little 256GB boot disk is laughable compared to the 38.4TB – up to 88TB compressed you can store on a single FCM.

Capacity however is just one thing, the real benefit of NVMe attached drives is really via the PCIe interconnect they use. By moving to PCIe based NVMe drives you unlock the potential in terms of bandwidth. A typical SAS attached SSD will be limited by the 12Gbit SAS interface, typically getting about 500-600MB/s per drive (dual ported). By using two 1 lane PCIe Gen3 interfaces, the FCM’s and industry standard NVMe flash drives we can push closer to 1GB/s per port, so 2GB/s per drive when maxed out. Scale this up to many drives (all without over-subscription on the PCIe bus) and you can deliver tens to hundreds of GB/s.

The final thing about NVMe and PCIe attach is the reduction in latency across the board. With the drive essentially being directly attached to the CPU itself (by means of PCIe) there is no more “middle man” – i.e. as SAS or SATA controller chip. In the SAS world, you send your data from the CPU over PCIe to the SAS chip. It then sends the data out over the SAS network. So the SAS chip and the PCIe (usually 8 lanes) into said chip becomes the bottleneck, meaning 8GB/s or such maybe the limit no matter how many drives you have, more more importantly it also adds latency. With the direct connect, the overall system latency is reduced, and this is partly how the IBM FlashSystem family can provide latency as low as 70 us (some 30% lower than most other major vendors) and even lower when using SCMs.

Of course NVMe over Fabrics is yet another area where you can see latency benefits, I’ve talked about the server side benefits this can bring previously, and of course that IBM was the first to market with an end-to-end all NVMe solution in the FlashSystem products.

The world has changed in the last couple of years, and so has the storage industry. NVMe as a connection interface over PCIe is here to stay and brings tangible benefits to all users – have you embraced the NVMe revolution?

To find out more, and hear the latest industry first, be sure to tune in next Tuesday for the announcement webcast.

PS. I have embraced my inner unicorn with the RGB on the new PC…

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