Intel Optane - when traditional SSD metrics don't tell the full story.

You may have noticed Intel banging the drum about Optane recently, but perhaps, like me you just thought it was another Intel branding exercise. Certainly when I initially looked at Optane I was wholly uninspired. 1.5TB Max capacity, hmm, seems low when other vendors and even Intel have 15 TB NVMe drives. Sequential read and write rates - not that impressive, basically the same as most high performance NVMe drives using a PCIe3 x4 link. Price, errrr, that is not cheap! In fact it is much more per GB than other vendors!

So what gives, why all the noise about this, low capacity, high price and seemingly, fairly normal performance SSD?

The truth is that Intel have not just developed another NAND SSD here, but a totally new type of storage based on a technology called 3D XPoint. Firstly it addresses the "wear" issues associated with NAND SSDs. No longer does additional NAND have to be added or DRAM caches utilised with wear levelling algorithms to ensure your NAND lasts as long as your server! With 60 DWPD the whole drive can be rewritten 60 times a day for 5 years, compared to 1 or 3 times for most normal NAND SSDs.

Not only that, 3D XPoint has a number of advantages over traditional NAND memory. It is of course, persistent like NAND (whatever is stored on it stays when the system is powered off, unlike DRAM). However, that is where the similarities end. 3D XPoint is a far more advanced solution which without going into huge technical jargon, means that it can be read and written without having to erase the data on there already. The latency of the drive is therefore vastly better than other solutions on the market.

Maybe that doesnt sound like a huge deal, but in real life it makes a huge difference to the amount of time the SSD spends executing the normal, real life, small transactions that operating systems and databases make consistently. This very important and 3rd metric that is often overlooked with SSDs is referred has always been a key metric on DRAM, latency is denoted by the CAS moniker in DRAM specifications (ie DDR4-2666 CAS19) with the lower number being better latency. Generally measured in picoseconds to microseconds for the top tiers (Cache/DRAM) and into milliseconds for SATA drives as capacities increase and connections become more convoluted.

3D XPoint SSDs have shown already in real life applications, up to 74% improvement in latency vs traditional NAND drives. Not only that but the underlying technology of 3d XPoint memory is many many times improved vs NAND in respect to latency. This is why 3d XPoint was developed - to address the processor hunger for data and bridge the gap between DRAM and normal NVMe and SATA SSDs.

3D XPoint comes in 2 flavours for Datacenter applications. The first being Intel DCPMM - basically DRAM form factor Optane modules that slot into the normal DDR memory slots on your server motherboard. These can be used to increase your memory capacity significantly offering high capacities when compared to DRAM at much lower prices. Imagine 3TB of Memory, with 512GB of commodity RAM and 2.5TB of Optane Memory allowing both persistence of storage and a massively increased memory footprint for a much lower cost than the DRAM portion. In fact systems exist that support up to 6TB of mixed DIMM and Optane memory.

On top of that we have the traditional SSD form factor of Optane - in 1.5TB max capacity and with the x4 interface using u.2 or PCIe interface. This model is significantly more cost effective than DCPMM and has differing usage models. Ideally sitting as a top tier of data storage in a Hyperconverged infrastructure, but also possible to use as an extension to DRAM like the aforementioned DIMM form factor.

There are a variety of usage models for Optane, in the main focused around database type applications and virtualised or converged storage infrastructures.

The end result is that applications like MySQL see a 3x improvement in transactions per second when using Optane - even vs Intel NVMe drives - that's huge!

Other applications that have been proven include, Apache Spark, VMWare vSAN, Azure HCI and a few others. Find out more here https://optanedifference.intel.com/

I hope you enjoyed the article, and feel free to reach out to us at the TechData solution factory to discuss Intel Optane as part of a wider technology solution. TechData offer everything from the underlying commodity servers and CPUs, to the key software to enable your application. - Thanks, Mark.