Enterprise Datacenter Hardware Assumptions May Be In For a Shakeup (acm.org) 100
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.
Can this entry be any more click bait? (Score:5, Funny)
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!!!
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or "this one weird trick"
Don't forget about the one weird trick.
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I tried it, it put my back out for a week, and I nearly lost an eye.
Wait, are we talking about the same thing?
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Discovered by an infrastructure engineering mom in ${Geolocate.getCounty()} County!
Brocade hates her!!
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I sent this to a co-worker. We came to the conclusion that this "Shakeup" really means "We just noticed whats been happening already for like a decade now".
Yes, actual storage being centralized and compute resources are consuming it and caching file access.... if you wash away the buzz this sounds a lot like existing enterprise visualization setups.
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if you wash away the buzz this sounds a lot like existing enterprise visualization setups.
I wonder what a dog thinks when it watches television?
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He probably doesn't think about washing away the buzz. Next article is going to declare THIS is now going to be the era of thin clients too. Get off my lawn kid.
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LOL, yeah ... my thinking was "it was a true fact, not an assumption".
Throw in some fundamentally new pieces to this (which as I gather is suddenly everything has it own damned CPU) ... and, yes, the rules will change.
Hundreds of CPUs spread across devices will cumulatively have more CPU power than the single CPU which has always been at the top of the food chain. All that really means is everything now has a ton of embedded compute power which previously wasn't there.
Things which used to be classed as sup
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Same here.
Now if they found a way to practically combine RAM and disk into one unified whole, and made the two faster than frig (and able to reallocate on-the-fly w/ minimal disruption as the workload changed, maybe on a curve or as load >= n )? That would be news.
TFA... TFA has a lot of stuff to sift through to get anything of note out of it at all, and it wasn't much.
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Towards the end of the article they specifically mention this scenario with NVDIMMs.
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You're not kidding about the supercomputer in a cracker jack box. The average iPhone now has as much or more compute power as a Cray Y-MP from the early 90s.
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LOL, maybe a little with the Cracker Jack box ... but, no, I really wasn't kidding.
For those of us old enough to remember when a gigabyte was a theoretical number nobody would ever encounter ... you can buy what used to be astronomical amounts of storage as an afterthought in the express checkout at Wal Mart for a couple of bucks.
I'm afraid these days to know how cheap, small, and ubiquitous a 1GHz chip is ... because there was a time that was considered munitions grade hardware which was covered under expo
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Technology changes, so does how to better use them.
Old technology long term storage was very slow. So we used to CPU calculate a lot of data. Think Mario and Luigi in the original NES They were 1 bitmap and you just swapped the pallets, as well many of the creator's same expensive bitmap image, and use the CPU to cheaply give them different color. As times goes on Storage is cheaper and faster. So we have independent bitmaps for Mario and Luigi so they are different in appearance, luigi being taller and
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> But lets get away from games and onto serious computing.
And games are not serious computing how? There are grand challenges that have been overcome in the technologies that power video games. Path finding, latency reduction, 3D computation, and so on.
Not to mention budgets that exceed that of some "enterprise" firms.
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Meh. This assumption wasn't even true before. Those of us that are actually in the trenches already know this. Some magical new technology change doesn't really alter things.
You actually have to pay attention to your workload and how your application is handling it.
It's nice that some academic or journalist has finally caught up.
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Actually that observation wasn't even true in the past. A lot of mainframes had very fast and complex I/O processors with central CPUs that weren't necessarily faster (depending upon what models you bought).
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A "paradigm shift" from "disruptive technology" that goes beyond "24/7"
The slowest thing in the datacentre ... (Score:4, Interesting)
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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While mostly true that the answer is usually/often network, there are some high data loads where actual database performance might still be a bottleneck and others where the actual calculations or other manipulations(=cpu) are the slow link so there is still a need to look at the values.
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In some cases the RAM speed may be the bottleneck, and that one sure is a hard one to analyze.
First you run 2 tasks concurrently on a 4-core (real cores, not hyperthreaded) machine, and get 2 tasks per second done. Then you run 4 of the same tasks concurrently, and get 3 tasks per second done.
All the CPUs show 100% utilization, yet you see only 50% gains instead of the expected 100%.
You say performant, I say performance... (Score:1, Offtopic)
Never seen the word "performant" until today. Must be an obscure five-dollar word that scientists love to toss around. Meanwhile, I'll stick with cheap performance as my word of choice.
https://en.wiktionary.org/wiki/performant [wiktionary.org]
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Re:You say performant, I say performance... (Score:5, Insightful)
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Language is a tool. Just because you're not versed in its intricacies doesn't mean that someone who is is inferior to you.
People who use buzzwords to hide the fact that they aren't really saying anything are tools. It's been a long time since I've read an academic article so full of bullshit.
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(slashdot lameness filter prevention plz ignore)
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"Performant" is an invaluable word. It instantly identifies those who use it seriously as people who may be safely ignored.
Speaking of invaluable, I have found that those who spew the most buzzwords in their vernacular also happen to control the budget.
In other words, tread lightly. The "PHB" wasn't born from pure fiction...
Re:You say performant, I say performance... (Score:4, Informative)
Performance is a noun. Performant is an adjective. I guess he could have said "faster"
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I thought that was "performer".
performant is to performer as informant is to informer.
Performant does not (necessarily) mean "faster" (Score:5, Insightful)
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.
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Performance is a noun. Performant is an adjective. I guess he could have said "faster"
performant [reference.com]
noun
a performer
Word Origin
based on informant, etc.
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Never seen the word "performant" until today. Must be an obscure five-dollar word that scientists love to toss around. Meanwhile, I'll stick with cheap performance as my word of choice.
https://en.wiktionary.org/wiki/performant [wiktionary.org]
Performance is a noun. Performant is an adjective, meaning "having (high) performance" (or performing well). If you stick with performance, be sure to reword your sentence so that it makes sense.
You're right, performance is a noun while performant an adjective. Most of the time, though, you can just say fast.
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An important exception occurs when we're talking about MTBF. Fast doesn't mean performant, at all.
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An important exception occurs when we're talking about MTBF. Fast doesn't mean performant, at all.
Right, then you can say something like reliable. We have now seen how useless the word performant really is. It's completely dependent on context. So it means nothing more than good yet takes three times the bandwidth.
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.
So either the word is relatively new, or in niche use.
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sorry, but "unabridged" means nothing with respect to the comprehensiveness of a dictionary -- except that if there is an abridged edition of the same dictionary the abridged version will have fewer words (or smaller definitions, or something).
Your conclusion is based on a flawed assumption. I've been using a small dictionary for around thirty five years now. I can't check it (the dictionary is at home), but based on frequency of word use over time and the quality of that dictionary I expect the word would
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Thank fucking Gawd. Finally, someone says something on slashdot based on fucking data. Wow.
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Well Looks to me like Oxford says webster can suck it: http://www.oxforddictionaries.... [oxforddictionaries.com]
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Concur. I am the proud possessor of a paper copy of the 20-volume Oxford English Dictionary. "Performant" isn't in the OED. "Performancer", as in "he / she who performs", however, is....
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A system which has good performance is said to be performant.
Your own link says this has been in used for at least since the 70s.
It's hardly a new term. It may only come up in specific contexts related to computing performance, but it ain't new.
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Re: I'm not reading all that (Score:4, Funny)
"SSDs exist now"
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And VMware made VSAN to go on top of them - RAID5 for compute/disk nodes w 10G network backplanes instead of SAS.
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Author doesn't know what he's talking about (Score:3)
This issue has been known to anyone using SSD's. The CPU's are still fast enough but the bandwidth between clients and servers (10Gbps is the average these days within a datacenter) no longer uses the full capacity of the disk subsystem (which is now connected at >10Gbps to each drive). Even having multiple disks in a single subsystem you can no longer use the capacity, not because of CPU issues but because of bandwidth issues between the CPU and the PCIe bus. That's why we're going away from large disk arrays and using 1 or 2U servers with 4-12 SSD drives and hooking them together with 'object storage' or other distributed storage mechanisms. That way you don't have a single point of failure and resource contention slowing you down.
But that's not the point, the point the article is making is that CPU's are getting too slow and that's not true. The CPU's are plenty fast and using any sort of off-loading mechanism would result in RAID controllers with CPU's that have to be just as powerful because if they aren't, you get the issues you have with current RAID controllers: they are slow and expensive (a single link to a 12Gbps chip is a bottleneck to an entire array of 12Gbps drives). Also you lose the scheduling, checksumming, hardware monitoring and all the other fancy things software-based solutions do these days.
Using CPU's as glorified RAID controllers is just fine and I don't foresee another solution as long as your software is fast and concise (eg. ZFS). If you start handing off anything to dedicated CPU's then you're just losing the control and customization a software based solution allows you to have.
ceph is cool and just want NON raid cards (Score:2)
ceph is cool and just want NON raid cards to link the back planes to the system board. Hardware raid was good in the past but now days multi node software is better with out the hardware raid lock in / losing 1-2 disks = data lost.
Authors maybe know what they are talking about (Score:2)
Well. I think the authors do have some points although at least some of them are existing in embedded systems (which execute directly out of Flash) for a long time:
* CPU cycle hungry, most efficient disk caching algorithms are not that efficient anymore once "disk" (or rather Flash) access manages to catch up to the CPU. Less efficient but also less resource hungry algorithms might be advantageous then.
* Issuing lots of read accesses in advance to keep your worker threads busy might only help in occupying R
The Shakeup (Score:1)
Comment removed (Score:3)
SSD's Exist and are really fast.... (Score:1)
Now tell me something I don't already know..
OK, OK, so CPU speeds are not trending up at quite the same pace and nonvolatile storage. But it's not like this has gone unnoticed or we haven't been making hardware changes to take advantage of this over the last decade in the data center. Just like we've adjusted to new power, network and virtualization technologies in the data center.
The real story is that CPU speeds are not trending up as steeply as they where 10 years ago, but we've been seeing huge leap
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Well there is new kernel tech for i
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Well there is new kernel tech for it (https://www.thomas-krenn.com/en/wiki/Linux_Multi-Queue_Block_IO_Queueing_Mechanism_%28blk-mq%29).
That is really interesting, thanks for pointing it out. I missed your question when you posted it:
When do you decide to have a system managed service (for example apache) or a /etc/init.d initscript ?
If it is a process I want to stay up, then I use inittab. Apache is a pretty good choice for an init service, another example is databases or messaging systems. However , if it is someone else's system I just do it how they do it to fit in.
For example, apache could be be set up in inittab with a 'respawn' directive, so if the process is terminated it restarts automatically, if there is a problem with the ser
The first sentence doesn't even make sense (Score:1)
What does it mean for a CPU to be "more performant" that an I/O device? They do totally separate things. You can't even measure them with the same units.
Is a drill "more performant" than a hammer?
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Your autism is showing! I'm sure you know exactly what was meant, but you're just being a pedantic dickweed by choice.
The measurements in this case are in terms of operations per unit of time, or if you prefer, the amount of time required per operation.
Typically, a CPU can perform one of its operations (executing an instruction) much, much, much faster than a spinning platter hard drive could perform one of its operations (reading or writing a sector of data).
So when both a CPU and a spinning platter hard d
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Is a drill "more performant" than a hammer?
Obviously you missed the boat. Both the hammer and the drill have OBSOLETE! Introducing, the Hammer Drill: https://en.wikipedia.org/wiki/... [wikipedia.org]
Article is kinda pie-in-the-sky wrong (Score:4, Interesting)
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
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A DRAM cell goes through trillions of cycles in its live time.
Typical DDR4 (2133) runs at a little over 1 GHz, or a billion cycles per second of operation.
We're in the quadrillions scale, not trillions.
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A DRAM cell goes through trillions of cycles in its live time.
Typical DDR4 (2133) runs at a little over 1 GHz, or a billion cycles per second of operation.
We're in the quadrillions scale, not trillions.
Maybe he meant "cycles during which its own state is changed". They get less wear coasting for a few quadrillion laps than they do altering the value a few trillion times.
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SATA, even 6 or 12GB SATA, will be going away for HPC application and it may go away for even more moderate performance systems. Direct PCI is even faster. Thats what the article is about. The speed of storage and memory are converging. That will change how we build systems.
It is food for thought... (Score:2)
The basic point of the article is dead on. The major assumption that I/O is extremely slow has driven the organization of computer architecture from the beginning. But, as the article noted, in the last few years, that equation can be changed drastically. The memory hierarchy is going to get more complicated: DRAM, NVDIMM, NVM, SSD, HD, Optical/Tape, and best using that hierarchy means that there are changes that need to be made.
For one, I think there will be a lot of research in this area. Just like modern