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Enterprise Datacenter Hardware Assumptions May Be In For a Shakeup (acm.org)
For the entire careers of most practicing computer scientists, a fundamental observation has consistently held true: CPUs are significantly more performant and more expensive than I/O devices. The fact that CPUs can process data at extremely high rates, while simultaneously servicing multiple I/O devices, has had a sweeping impact on the design of both hardware and software for systems of all sizes, for pretty much as long as we've been building them. This assumption, however, is in the process of being completely invalidated.
Yes!
For the entire careers of most practicing computer scientists, a fundamental observation has consistently held true... and you won't believe what happens next!!!
This piece is citing articles written in 2005 as "ye olde world" and saying "OMG! something amaaaazing has happened.
Well, those 10 years represent 2 or 3 generations of datacentre hardware, depending on how you amortise your assets. So if the author has only just woken up to SSDs or SCMs then what have they been doing for the past decade?
In practice, the biggest bottleneck in the datacentre has been the network for a longish time. And the biggest bottleneck in most systems is the user's think-time. It is that last aspect which lies at the heart of multi-user systems.
However, the guy does have a point: the need for "olde worlde" performance management - designing the bottlenecks out of a system and diagnosing where the choke-points are (ans. the network) when things slow down has largely disappeared. But as for the rest of his stuff? Yes, we know all that.
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Performance is a noun. Performant is an adjective. I guess he could have said "faster"
"SSDs exist now"
Language is a tool. Just because you're not versed in its intricacies doesn't mean that someone who is is inferior to you.
Linux, you magnificent bastard, I read the fucking manual!
Performant is actually a pretty useful word in place of "real" ones like "faster", because "performance" is a word that can change meaning depending on what you consider to be good (or desired) performance.
Maybe good performance means that it's using all of the cores on a CPU well. maybe it means that it's not using much of the system at all, but is using the network very well, or work is spread out across a cluster in an extremely balanced fashion. "Faster" may be a by-product, but it may not, because people using the word "performant" often value stability over absolute speed.
I guess the closest concept "performant" comes to is being well-balanced, or perhaps meeting some goal you had set during design.
So don't be too dismissive of a new word, it can be the case a new word was made because old ones wouldn't really fit without a lot of verbosity.
"There is more worth loving than we have strength to love." - Brian Jay Stanley
At least, not totally correct. Memory bus non-volatile storage such as Intel's X-Point stuff still requires significant cache management by the operating system. Why? Because it doesn't have nearly enough durability to just be mapped as general purpose memory. A DRAM cell goes through trillions of cycles in its live time. Something like X-Point might be 1000x more durable than standard flash, but it is still 6 orders of magnitude LESS durable than DRAM. So you can't just let user programs write to it however they like.
Secondly, in terms of data-center machines becoming obsolete. Also not correct. SSDs make a fine bridge between traditional HDD or networked storage and something like X-Point. For two reasons: First, all data center machines have multiple SATA busses running at 6GBits. Gang them all together and you have a few gigabytes/sec worth of standard storage bandwidth. Secondly, you can pop nVME flash (PCI-E based flash controllers) into a server and each one has in excess of 1 GByte/sec of bandwidth (and usually much more).
Third, in terms of memory management, paging to/from SSD or nVME 'swap' space, or using it as a front-end cache for slower remote storage or spinny disks, already provides servers with a fresh new life that means they won't be obsolete for years to come.
And finally there is the cost. These specialized memory-bus non-volatile memories are going to be expensive. VERY expensive. To the point where existing configurations still have a pretty solid niche to play in. Not all workloads are storage-intensive and these new memory-bus non-volatile memories don't have the density to be able to replace the storage required for large databases (or anywhere near it).
So, the article is basically a bit too pie-in-the-sky and ignores a lot of issues.
-Matt