Before we begin, something needs to be clear: Although dual-ported NVMe drives are not yet cost effective, the architecture of Nimble Storage is NVMe-ready today. And always remember that in order to get good benefits from NVMe, one needs to implement it all the way from the client. Doing NVMe only at the array isn’t as effective.
The cardinal rule for enterprise storage systems is to never compromise when it comes to data integrity and resiliency. Everything else, while important, is secondary.
Many storage consumers are not aware of what data integrity mechanisms are available or which ones are necessary to meet their protection expectations and requirements. It doesn’t help that a lot of the technologies and the errors they prevent are rather esoteric. However, if you want a storage system that safely stores your data and always returns it correctly, no measure is too extreme.
Before we begin: This is another vendor-neutral post. I realize there may be no architecture that can do everything I’m proposing, but some may come closer to what you need than others. Whether you’re a vendor or a customer, see it as stuff you should be doing or be asking for respectively…
I wanted to bring this crucial issue to light since I’m noticing several storage vendors being either cavalier about this or simply unaware.
I will explain why solutions that don’t offer some sort of automated, live SSD firmware update mechanism are potentially extremely risky propositions. Yes, this is another “vendor hat off, common sense hat on” type of post.
In modern storage devices (especially All Flash Arrays), extensive data reduction techniques are commonplace and expected by customers.
This has, unavoidably, led to various marketing schemes that aim to make certain systems seem more appealing than the rest. Or at least not less appealing…
I will attempt to explain what customers should be looking for when trying to decipher capacity claims from a manufacturer.
In a nutshell – and for the ADD-afflicted – the most important number you should be looking for is the Effective Capacity Ratio, which is simply: (Effective Capacity)/(Raw Capacity). Ignore the commonly quoted but far less useful Data Reduction Ratio, which is: (Effective Capacity)/(Usable Capacity).
Ultimately, as a customer you shouldn’t even care about ratios. Only about the true effective capacity you can safely use.
Important: Any time you see any vendor quoting a ratio, they always quote the data reduction ratio. So, it is crucial that you don’t calculate effective capacity by multiplying that ratio times raw, but rather times usable. I had to edit the article to add this since I recently spoke to a customer that was making this grave mistake (various vendors only gave them the raw capacity and the data reduction ratio!)