A Practical Approach to NVMe

 

In 2018, NVMe is coming to a flash system near you. There are two basic methods the various vendors are using to bring NVMe to their customers. Most all-flash vendors are delivering an NVMe-only system, and then retrofitting their systems with NVMe drives and connectivity. There is a second group, a new round of start-up vendors that are also bringing NVMe-only systems to market. Most of these vendors are end-to-end NVMe, using both internal NVMe connectivity and external NVMe connectivity for the attaching servers. At Tegile, we are taking a different approach by leveraging our intelligent data movement technology to deliver a performance-correct and cost-correct platform to the market.

 

The Problem with NVMe Only

There are two problems with the NVMe only strategy. First, it’s more expensive. NVMe drives and especially the components required to connect to NVMe drives, cost more than today’s standard SAS connections. It is reasonable to expect that NVMe drives and connections will come down in price, but that will take time. The second problem with an NVMe only strategy is the overwhelming majority of data centers can’t take advantage of the system’s potential performance. Most data centers have only a fraction of their data set that can justify NVMe. Of course, over time, the cost of NVMe will go down, and the number of applications that can justify NVMe will increase, but that time is not today nor is it likely to be anytime soon.

Ironically, a better case can be made for end-to-end NVMe, meaning NVMe over a Fabric network connecting to an NVMe based all-flash array. Again, most data centers don’t need this level of performance and even the few that do, have a particular use case within the data center that could justify it. For those few use cases, end-to-end NVMe makes sense. Nevertheless, even with NVMe connectivity, the entire flash array probably does not need to be NVMe.

Unquestionably, applications and use cases will eventually catch up with the potential of NVMe based storage. However, for today, all-NVMe and end-to-end NVMe are overkill for most data centers and by the time those data centers catch up, we will be on another generation of NVMe system, making it difficult to justify the purchase by claiming that the system is “future proof.”

 

Practical NVMe

A more practical approach to NVMe is to leverage NVMe-based flash as a buffer to SAS-based flash, essentially creating a hybrid flash array similar to the flash/hard disk drive hybrid arrays of the past. This type of system will require that the system have built-in data movement intelligence that moves data from the NVMe tier to the SAS tier. However, most all-flash vendors lack this feature. It was cheaper (for them) to create an NVMe-only system for which customers pay extra.


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