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โ€บ "Objective review" - can you trust it? The truth, a *real* comparison and news
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"Objective review" - can you trust it? The truth, a *real* comparison and news

jsgjsg Member, Resident Benchmarker

Recently there was an "objective review" of my benchmark program which actually was intended to and done to discredit my vpsbench (my software), my work for the community, and me (as basically admitted by the OP himself).

So, let's look again and this time properly. What do I mean by 'properly'?

  • Said OP explained that AWS can be trusted because they would not lie to large corporate customers and hence his "review" based on some testing on AWS was somehow fair and proper. Unfortunately though even a quick search leads to quite a few results where Amazon/AWS is accused of lying; some even provide evidence. More importantly though we seem to have no reason to presume that said OP is a 'large corporate customer', so his argument fails anyway. Plus how can he verify what AWS says? Can he/we even really know the hardware and other relevant details of what his VM was running on? In short, his whole approach, basis, and argument were flaky.
  • Said OP did not even make the effort to use vpsbench properly, let alone doing an even just halfway fair comparison. Unlike him I did use fio in a way that leads to similar tests.
  • I used real physical hardware which I actually can really control. No one else using the node, no other who knows what software running on the node.
  • My main goal is not even to attack said OP (which is why I do not name him); my main goal is to do properly what he did on shaky grounds and sloppily as well as obviously biased.

So, let's go. The hardware is a system build and installed only and exclusively for this test, an Asus mainboard with a Ryzen 1700 and 16 GB memory (DDR4, 3000MHz, 16 clk) and two physical drives which are not used for anything else other than the tests. One of those is an old OZ Vertex SSD (don't care, just think "some SSD") and the other one is a Seagate Firecuda which I intentionally chose because it's a spindle ("HDD") but one with a built-in flash cache.
The OS is devuan (basically debian 10 without systemd), freshly installed on a new and unused M2 SSD. At any point in time only the test candidates, and only one of them, were running and the system was a plain default (server) install.
In short, a really fair and unbiased test setting.
fio was a default (apt) install too, it's v. 3.21. Both vpsbench and fio were tasked to do 2048 writes and reads of 64 K blocks for a total test size of 128 MB in direct/sync mode and so was 'dd'.

Here are the 4 calls of fio, similar to what my program does, with '$1' being the path to the root of the tested device:

fio --name=wr_seq_64K --ioengine=sync -fdatasync --rw=write --bs=64K  --iodepth=1 \
--numjobs=1 --size=128M --gtod_reduce=1 --direct=1 --filename=$1/test.fio --group_reporting
    echo 

fio --name=wr_rnd_64K --ioengine=sync -fdatasync --rw=randwrite --bs=64K \ --iodepth=1 --numjobs=1 --size=128M --gtod_reduce=1 --direct=1 --filename=$1/test.fio --group_reporting
    echo 

fio --name=rd_seq_64K --ioengine=sync --rw=read --bs=64K --iodepth=1 --numjobs=1 \
--size=128M --gtod_reduce=1 --direct=1 --filename=$1/test.fio --group_reporting
    echo 

fio --name=read_rnd_64K --ioengine=sync --rw=randread --bs=64K --iodepth=1 \ --numjobs=1 --size=128M --gtod_reduce=1 --direct=1 --filename=$1/test.fio --group_reporting

followed by vpsbench, then hdparm ('hdparm -tT [device]') and finally dd ('dd if=/dev/zero of=[tested devices root dir] bs=64k count=2048 oflag=sync').

Before showing the result I have to mention two things:

  • vpsbench is a new and enhanced version (2.4.0) with more realistic read results (learn more later)
  • 'hdparm -tT' does test the device (rather than via a file) and it does reads only, but I found it interesting and potentially valuable because it works on a deeper level.

Here are the results:

    SGF                                     |    OZV            
            MiB/s   Iops    MiB/s%  Iops%   |MiB/s  Iops    MiB/s%  Iops%
----- *cache ON* --------------------------------------------------------                                
Fio WrSeq   129,6   2056                     122,6   1846        
Fio WrRnd   129,3   2052                     158,1   3038        
Fio RdSeq   131,7   2089                     157,9   3038        
Fio RdRnd   16,0    31,51                    141,4   2388        

vpsb WrSeq  4,9                              98,2            
vpsb WrRnd  4,9                              120,2           
vpsb RdSeq  129,4                            138,2           
vpsb RdRnd  550,9                            1125,9          

hdparm C    470,0                            200,0           
hdparm NC   129,8                            204,4           

dd sync     6,2                              120,0           

----- *cache OFF* --------------------------------------------------------                               
Fio WrSeq   129,2   1977    99,7    96,2     100,4   2043    81,9    110,7
Fio WrRnd   130,7   2068    101,1   100,8    161,4   3129    102,1   103,0
Fio RdSeq   128,9   2048    97,9    98,0     164,0   3200    103,9   105,3
Fio RdRnd   17,1    35,89   106,9   113,9    144,5   2494    102,2   104,5

vpsb WrSeq  0,9             18,4             96,2            98,0    
vpsb WrRnd  0,8             16,3             119,9           99,8    
vpsb RdSeq  122,6           94,7             132,4           95,8    
vpsb RdRnd  467,2           84,8             1120,5          99,5    

hdparm C    61,0            13,0             200,1           100,1   
hdparm NC   129,3           99,6             203,3           99,5    

dd sync     0.91            14.68            80 - 120        ??   

First an apology in case I f_cked up formatting (in my editor it looks fine).

What you see are two result sets. The top half shows the results with the OS cache not disabled that is, what most users work with. The lower half is with linux' disk caching disabled ('hdparm -W 0 [device]'). On the left ("SGF") are the Seagate Firecuda results, on the right ("OZV") are the results of the OZ Vertex SSD.
'hdparm -tT [device]' does two tests, one with cache ("C") and one ("CD") with cache disabled, so you see 2 result lines.
Only the fio results use all columns because (so far) only fio shows IOPS.
Note the additional columns in the lower half, which show the results as a percentage of the results in the upper half that is cache disabled results vs. cache enabled results expressed in percent, so a value below 100 means that the result is lower than that with cache enabled and one with above 100 one that is higher.

Interpretation:

No matter with linux' disk caching enabled or disabled fio largely shows quite similar results, which clearly indicates that something weird is going on. Note that not only vpsbench but also hdparm and dd show quite different results depending on the linux disk cache being active or not. dd funnily delivers varying results on the SSD, but that's no problem because I used it just as a basic orientation and check point.
Only fio delivers pretty much the same results which is not credible. All other tests, deliver drastically lower results when the OS cache is disabled with only one exception on only one disk.
But there is more. fio also tells us that random reading is slower on the drive with a built-in cache than random writing, no matter whether the OS cache is enabled or disabled. And we are not talking about a small difference but about reading not even achieving 20% of write speed! With the SSD it's the sequential writes that drop significantly with the OS cache disabled, random writes though, which are far more in need of caching just keep their speed but for the sake of fairness all other tests don't lose speed either with cache disabled, which leads me to the the assumption that that SSD actually has some (DRAM I guess) cache built-in too without telling (or me having forgotten it).

But one thing is clear: No, fio does not seem to be "the reference". It rather is the outlier. In fact I'm quite content with at least the new version of vpsbench. Spindles (at least consumer HDDs) are bloody much slower than SSDs and the still high but (now) in a reasonable region read numbers from vpsbench do match my experience with the tested disks quite well. Turn the cache off and read speed goes significantly down while write speed goes brutally down.

But the maybe most important lesson is that there is no reference. Use 4 benchmarks and you get 4 different results, simple as that. Second point: Every benchmark shows a few weird results; that's not even surprising when considering the different approaches, parameters and flags used as well as the complexity of modern systems.

And well noted, we are talking about a dedi here. On a VPS yet another layer of caching weirdness and layers are added on top and one can usually not change anything on the node level and even less so if a Raid or disk controller with its own cache enters the game as is often the case with node hardware.

But here is the good news: I have carefully checked the vpsbench source code many times and the really important point is this: It's quite meaningless whether vpsbench (or any other benchmark) shows read or write results higher or lower than another benchmark. The relevant point is that it does consistently whatever it does so that the result sets between providers and VPSs are fair and comparable.

Thanked by 1Arkas

The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

ยซ134

Comments

  • jsgjsg Member, Resident Benchmarker
    • "King" - I can understand that some are quite provoked by that word in my tag - but please, pretty please, keep in mind that it was not me who chose that tag! Frankly, I was a bit shocked myself and not exactly happy with that choice, but I didn't complain because I was and am very confident that that tag was created with a kind intention. But yes, if I myself had chosen a tag it would have been much more modest, probably something like "resident benchmarker". It makes absolutely no sense, no sense at all, to dislike or bash me for that "king" tag.
    • "King" 2 - As I said, I can understand that the "king" drives some of you angry, so I've asked for my tag to be changed to something more modest. I'm glad to report that @jbiloh reacted with understanding and kindness and changed my tag and I myself feel better with the new tag too.
    • oh so evil, arrogant jsg who nevar accepts or listens to feedback or criticism, just enhanced vpsbench considerably (v.2.4.0) and solved the "ridiculously high read results" problem some of you have criticized. Well noted, quite shortly after creating another enhanced version, also based on user feedback (v.2.3.0). The decisive point is not me being somehow arrogant and evil, it is how feedback or criticism is served. Do it politely and constructively and I'll listen and work to include your feedback in a new version. Do it in a bashing, insulting, primitive way and I'll just think "a__hole without manners" and ignore you or hit back.
    • not listening jsg 2 - I'm happy to report that I'm close to finishing yet another new version (v.2.5.0) which also computes and shows IOps. Based on listening to feedback ...
    • your rights - What exactly is your right to demand anything from me anyway? Keep in mind why and what for I created vpsbench. I created it for myself and for a particular purpose because I didn't find another tool I considered adequate for what I had in mind. The reason to share my work/program is simply that I've been asked to please share it, and so I did. Everything I did here was unpaid and for free and so was my giving away the program. I don't get it, why some here seem to think that they have any rights whatsoever wrt my work. You have none, period. What you do have is the right to simply ask politely - and usually I'll move for you.
    • Is fio crap then? - No, I don't think so. The most important point is that fio is an entirely different tool with entirely different goals. For a start fio is a pure disk benchmark while vpsbench is a tool providing diverse tests and information. Second, fio is a quite complex tool in more than once sense. To use it properly and to really understand requires a considerable level of understanding and know-how and to use it in a wrong way or a way that makes little sense is very easy (as is demonstrated by some scripts using fio). Actually I think that fio is a good and useful tool for quite a few use cases, but not for benchmarking VPSs. I seem to have discovered some weird spots but that doesn't change my view that fio is a good tool if used properly by someone who really knows what he's doing. Example: "--numjobs=4 --iodepth=64" simply doesn't make a lot of sense on often rather small 1 vCore, 1 or 2 GB VPSs.
    • "vpsbench is just some program" - No, not really. vpsbench is - and has been designed from the get go as - one part in a larger chain. Other parts are e.g. the "controller" actually running vpsbench on a VPS to be tested and do run it in a way useful for us. Example: In our use case not every provider is nice and honest, so I want the timing of benchmark runs to be unpredictable. Or, another example. some may have their heaviest loads during business hours, others during the night, so I want to collect data throughout all times of day and night. Also the whole chain has been designed in a way to quantify and show spreads and the average to show you what you can expect not only at some moment and within what range your VPS will likely perform.
    • "But vpsbench delivered sometimes ridiculously high read results!" - Yes, that criticism is justified (Thanks e.g. @Falzo) and I wasn't exactly happy about that myself. But as I said, vpsbench and all my reviewing here are basically a hobby activity and good will service done for free to contribute my part to our community. That also means that I have only limited time for it and some problems need quite a bit of research, tinkering, testing, etc. This problem is one of those. Let me explain: vpsbench first writes out data and later reads them back - and that hundreds of times without doing anything else on the test systems. So, where should the data to be read come from other than from the write tests? One can get linux to largely write data to a drive without lots of caching and one can ask linux to please empty the data already in cache (e.g. from a write shorty before, cough, cough) but there's still always the node beneath the tested VPS with its own caching layers (hint: have a look just at proxmox diverse caching settings/choices ...). I think I finally have found a reasonably good way and as the above results show it seems to work much better now. But I'll still have to do some more testing in different settings.

    Summary: You don't like vpsbench? Fine, no problem, simply don't use it; wrote it mostly for myself anyway. You think that tool XYZ is much better than vpsbench? No problem, just use that tool. You want to hit at me because you think that tool XYZ is much better than mine? My advice: Don't. For one it's not nice, nor is it needed. But also, you should be well prepared; a quick and dirty hit won't do and risk to lead to a reaction you might not like.
    You don't like my reviews? Fine, no problem, just don't read them and find some you like.
    And rest assured that I do care about vpsbench being and evolving ever more into a realiable good tool - in fact I care more than virtually anyone here and I invest the efforts and work.

    Finally a word of advice: Do NOT take any benchmarks numbers as absolute or as "reference"! Rather take the results as "compared to other systems". And always look (when available like in my reviews) at the spread, too!

    Thanked by 1AlwaysSkint

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • @jsg said:
    Only fio delivers pretty much the same results which is not credible. All other tests, deliver drastically lower results when the OS cache is disabled with only one exception on only one disk.

    Isn't fio --direct=1 parameter used to make sure the test will not use cache? Your summary for fio is wrong because you use wrong parameter.

    CMIIW

    ๐ŸŒˆ A simple uptime dashboard using UptimeRobot API https://upy.duo.ovh
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  • jsgjsg Member, Resident Benchmarker

    @chocolateshirt said:

    @jsg said:
    Only fio delivers pretty much the same results which is not credible. All other tests, deliver drastically lower results when the OS cache is disabled with only one exception on only one disk.

    Isn't fio --direct=1 parameter used to make sure the test will not use cache? Your summary for fio is wrong because you use wrong parameter.

    CMIIW

    No. Your nonsensical ignorant "conclusion" is wrong. I did use '--direct=1' ... as can be seen in the calls which I did provide.

    But thanks for yet another example of "I can't be bothered to actually read. Just willy nilly asserting something has to suffice".

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • No we neither trust you nor your shady experiments.

  • Oh I don't think I'm going to be reading an essay...

  • Dethroned king, lost credibility, shatered authority. Steve the evil has obtained his goal.

  • vpsbench is a new and enhanced version (2.4.0) with more realistic read results
    just enhanced vpsbench considerably (v.2.4.0) and solved the "ridiculously high read results" problem some of you have criticized

    Basically the King admitted previous version of vpsbench was indeed generating erroneous results, so he dethroned himself and quickly fixed the bug.

    404 drama not found

  • @yoursunny said:

    vpsbench is a new and enhanced version (2.4.0) with more realistic read results
    just enhanced vpsbench considerably (v.2.4.0) and solved the "ridiculously high read results" problem some of you have criticized

    Basically the King admitted previous version of vpsbench was indeed generating erroneous results, so he dethroned himself and quickly fixed the bug.

    Wil you wait for rethroning?

  • jsgjsg Member, Resident Benchmarker
    edited September 14

    Uhm, the "King" himself asked for having his tag replaced by something more modest. No dethroning, sorry. I know some would have loved that.

    I'm not at all surprised that the bottom dwellers of the 85% crowd fail to understand that but a PhD (or PhD in spe)? Strange.

    @yoursunny said:

    Basically the King admitted previous version of vpsbench was indeed generating erroneous results, so he dethroned himself and quickly fixed the bug.

    Actually the "King" already "admitted" - and even explained the reason - not erroneous but too high read results quite a while ago. But now he has found a way to solve that problem.

    But even assuming you were right: How despicable a creature must be to turn against someone that solved a problem they complained about! Or in other words, thanks for clearly and unmistakably demonstrating your true attitude and intention which is, no matter what I do, no matter how I act you will find a way to turn that against me.

    Thanked by 1Arkas

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • fragpicfragpic Member
    edited September 14

    yabs or gtfo!

    You got wrecked on the other thread. It's time for you to move on.

  • jsgjsg Member, Resident Benchmarker

    @fragpic said:
    yabs or gtfo!

    You got wrecked on the other thread. It's time for you to move on.

    So, you get to decide what software I use? I don't think so.
    Try to impose your rules on someone else.

    And now, to use your words, gtfo!

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • deankdeank Member, Troll

    The end is nigh.

    If you wish to join Nigh sect, adopt my avatar as your own and believe in the end.

  • tldr pls?

    "They said it's RAID 5" - geekypixal

  • deankdeank Member, Troll

    All of his "reviews" were false and heavily favored hosts he reviewed.

    If you wish to join Nigh sect, adopt my avatar as your own and believe in the end.

  • @jsg said:

    @fragpic said:
    yabs or gtfo!

    You got wrecked on the other thread. It's time for you to move on.

    So, you get to decide what software I use? I don't think so.
    Try to impose your rules on someone else.

    And now, to use your words, gtfo!

    Nobody on this forum was asking for dd's or hdparm test results, just yabs. I'm curious whether yabs would reproduce the fio result or show a more reasonable speed.

  • jsgjsg Member, Resident Benchmarker
    edited September 14

    @TimboJones said:
    Nobody on this forum was asking for dd's or hdparm test results, just yabs. I'm curious whether yabs would reproduce the fio result or show a more reasonable speed.

    So what? Am I your servant? I can use whatever tools I please, without you asking or not, and I wanted more than just vpsbench and fio.

    As for yabs, that is using fio anyway, albeit in a way I don't care about. If you think that yabs is great, you are free to use it - and unlike my "opponents" act towards me I do not try to bash, attack, smear, and discredit yabs users.

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • @jbiloh the cloudflare pop up block is happening again...

    There's several things to note:

    1. Of course the vertex ssd has 64MB cache. You probably should find that out, as well as if the firecuda has 4GB, 8GB or 16GB of cache.

    2. You're concerned about the formatting but not the period vs commas? I can't make sense of the units.

    3. Write random is 100 times worse than read and doesn't strike you as odd? You're writing to cache! It shouldn't be slow!
    4. you measured 1120 with the Vertex, over double the sata spec. It's double the drive's own specs. That is immediate red flag (for the millionth time)
    5. You start this thread to say it was in response to a hit piece, despite showing results that you confirmed and thought you fixed as a result.

    This is epic fail. You don't understand what results to expect.

  • jbilohjbiloh Administrator

    Long live the king!

    That said, JSG asked that the title be changed to something more modest, and I happily complied. I was the one who came up with "Server Review King" originally.

    JSG spends a lot of time in service to the community with all of his contributions. There should be some appreciation and respect for that even if you disagree with the methods.

    Seems like @jsg is working to improve his systems further which is great to see.

    @TimboJones please PM the details of what is happening to you regarding CF and I will do my best to fix it. Sorry for the inconvenience caused. I really try quite hard to make things as best possible when it comes to our security without getting in the way more than needed.

    Thanked by 2jsg Arkas
    Jon Biloh
  • jsgjsg Member, Resident Benchmarker

    someone serially breaking agreements said:

    1. Of course the vertex ssd has 64MB cache. You probably should find that out, as well as if the firecuda has 4GB, 8GB or 16GB of cache.

    I guessed and said so much myself, but whatever cache it has or has not, it has for all candidates, vpsbench, fio, hdparm, dd.

    1. You're concerned about the formatting but not the period vs commas? I can't make sense of the units.

    Well, I happen to live in a region where it's done the other way round. Simple solution: just do what you expect half of the world to do; mentally swap commas and dots.

    1. Write random is 100 times worse than read and doesn't strike you as odd? You're writing to cache! It shouldn't be slow!

    But it is, just like with/very similar to dd.

    1. you measured 1120 with the Vertex, over double the sata spec. It's double the drive's own specs. That is immediate red flag (for the millionth time)

    How pathetic ("millionth time"). And: you are wrong. Because a read call does not necessarily go to the device/via Sata.

    And of bloody course you are totally biased (again) and mention only what fits your agenda. fio showing some reads to be much, much slower than writes.
    THAT is what really happens " for the millionth time". Whenever I address any of your "criticism" all I get is more of the same.

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • @jsg said:

    @TimboJones said:
    Nobody on this forum was asking for dd's or hdparm test results, just yabs. I'm curious whether yabs would reproduce the fio result or show a more reasonable speed.

    So what? Am I your servant? I can use whatever tools I please, without you asking or not, and I wanted more than just vpsbench and fio.

    That is true in the same way that someone can say that you are wrong and refuse to give proof because they are "[not] your servant". If you want to properly prove that you are right, you have to meet the burden of proof of the people you're trying to convince, and right now you're refusing to use what this forum sees as the "gold standard" for benchmarks.

    I think there's a bigger issue right now though. @stevewatson301's "hit piece" provided a lot of strong evidence that you have failed to disprove which is why it garnered so much attention, and you're only countering his points by responding in bad faith - you aren't being sneaky and everyone can see through your gatekeeping and gish galloping. I think you're too defensive right now to come to a proper conclusion to this issue, and I'm tired of watching you dirty your own reputation further. Could I propose a moderated debate or something (@jbiloh I'm sure it would be great content too) where you find an impartial moderator to allay the concerns of bad faith on both sides?

  • AlwaysSkintAlwaysSkint Member
    edited September 14

    @jsg said: Simple solution: just do what you expect half of the world to do; mentally swap commas and dots.

    Too f'kin obvious for those blinkered people who just like to attack others, for "shits & giggles". ;)
    [Fifths of an inch and millimetres, anyone?]

    Thanked by 2dahartigan jsg

    Then=sequence/consequence; than=compare || Brought=bring; bought=buy || Paid=NotSkint; payed=some naval thing || Staff=group of workers; Staffs=bunch of sticks || Stuff=things; stuffs=to force in.

  • @jsg said:

    @chocolateshirt said:

    @jsg said:
    Only fio delivers pretty much the same results which is not credible. All other tests, deliver drastically lower results when the OS cache is disabled with only one exception on only one disk.

    Isn't fio --direct=1 parameter used to make sure the test will not use cache? Your summary for fio is wrong because you use wrong parameter.

    CMIIW

    No. Your nonsensical ignorant "conclusion" is wrong. I did use '--direct=1' ... as can be seen in the calls which I did provide.

    But thanks for yet another example of "I can't be bothered to actually read. Just willy nilly asserting something has to suffice".

    I think you understood him wrong. he saw that you indeed used that flag in all fio calls. therefore he (and me too) thinks your cached results are actually not cached for fio anyway. simply because fio bypasses the cache, no matter if you deactivated it via hdparm or not ;-)

    so that would be a reason, why the fio result are that consistent - the direct=1 makes it that way.

    would you provide your newer version of vpsbench? I'd be interested in running it again on my dedi with the regular HDDs. any details on what you changed?

    on another note, the IOps shown for the spindle are to high anyway, it should be max 200 even for a very fast one. this suggests that the overall size of 128MB is too small for a reliable measurement and indeed hitting the HDDs cache only.

    the write speeds seem quite slow but could actually make sense considering that it's a product of iops*bs so 4.9MB/s at 64k blocksize result in somewhat 80 IO per second (which again seems reasonable for a spindle.

    that still leaves me wondering why the difference between write and read speed is that large. and especially that random reads regularly achieve higher speeds than sequential ones even on HDD will never make sense to me. it feels a bit like if your read routine suffers from parallelism or something like that, while writes do not. just sayin' ... unprofessional personal opinion that is.

    UltraVPS.eu KVM in US/UK/NL/DE: 15% off first 6 month | Netcup VPS/rootDS - 5โ‚ฌ off: 36nc15279180197 (ref)

  • AlwaysSkintAlwaysSkint Member
    edited September 14

    Kudos @Falzo for sticking to figures, in a dignified fashion. B)

    [Needs to find that shift key though! :p ]

    Then=sequence/consequence; than=compare || Brought=bring; bought=buy || Paid=NotSkint; payed=some naval thing || Staff=group of workers; Staffs=bunch of sticks || Stuff=things; stuffs=to force in.

  • FalzoFalzo Member
    edited September 14

    @AlwaysSkint said:
    Kudos @Falzo for sticking to figures, in a dignified fashion. B)

    thanks for the flowers. I am simply interested in any kind of benchmarking, especially disks as this has a long tradition and a few years back you'd only see dd everywhere and even that could be done wrong depending on some few options.

    there are a few (physical) limitations and relations between a few factors. the rest is pure math, so yes I am questioning numbers (not only vpsbench, but often others too) and usually develop some curiosity about the reason.

    that does not neccessarily mean any benchmark is doing anything wrong. could simply be the intention to measure something else than what I would expect when seeing the result. yet could also be some logical flaw that nobody saw before ๐Ÿคทโ€โ™‚๏ธ

    tl;dr; I like riddles.

    UltraVPS.eu KVM in US/UK/NL/DE: 15% off first 6 month | Netcup VPS/rootDS - 5โ‚ฌ off: 36nc15279180197 (ref)

  • jsgjsg Member, Resident Benchmarker

    @drunkendog said:
    That is true in the same way that someone can say that you are wrong and refuse to give proof because they are "[not] your servant".

    Nope. not comparable. If I just make some statement and someone says that I'm wrong without providing proof that's OK. Not nice but OK. But here one side (me) has invested massive work, efforts, and time and to just say that I'm wrong is not enough, just like it wouldn't be enough if I did that to someone who has invested massive work, efforts, and time.

    If you want to properly prove that you are right, you have to meet the burden of proof of the people you're trying to convince,

    Wrong again, because this isn't about me, out of the blue, claiming to be right. It's not even an acceptable defense situation where I have to defend e.g. a dissertation and where both sides must meet certain standards. This is a situation where some just throw assertions at me, meeting no standards whatsoever, but hold me to strict standards and as default position, reject whatever I submit.

    Plus, and that's important: In a dissertation defense or say a job interview there is something to be gained if one is successful. Here however I have nothing to gain, I want nothing, I'm simply sharing some work I did. If one likes it, one takes it, if one does not like it, one doesn't take it.

    and right now you're refusing to use what this forum sees as the "gold standard" for benchmarks.

    I have shown that not only is it not the "gold standard" but actually there is no "gold standard" at all (incl. my program). And btw, "we like/prefer XYZ" doesn't make XYZ a gold standard.

    I think there's a bigger issue right now though. @stevewatson301's "hit piece" provided a lot of strong evidence

    How can something that does not even stand on a solid basis provide "strong evidence"? You simply call it that because you want to see it as "strong evidence". that however doesn't make it so.

    that you have failed to disprove which is why it garnered so much attention, and you're only countering his points by responding in bad faith - you aren't being sneaky and everyone can see through your gatekeeping and gish galloping.

    Thanks for your confession. You should keep it private when you talk to yourself.
    Yet another case of "It is so, because I say so, but you, jsg, must prove everything you say - and to my "standards!". Sorry, that doesn't work with me.

    I think you're too defensive right now to come to a proper conclusion to this issue, and I'm tired of watching you dirty your own reputation further.

    Do I, really? Nope. I "dirty my reputation" only with a few who would accept nothing I do or say and who want to hold a kangaroo court session with the verdict ready before the session began.

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

  • @Falzo said:

    @jsg said:

    @chocolateshirt said:

    @jsg said:
    Only fio delivers pretty much the same results which is not credible. All other tests, deliver drastically lower results when the OS cache is disabled with only one exception on only one disk.

    Isn't fio --direct=1 parameter used to make sure the test will not use cache? Your summary for fio is wrong because you use wrong parameter.

    CMIIW

    No. Your nonsensical ignorant "conclusion" is wrong. I did use '--direct=1' ... as can be seen in the calls which I did provide.

    But thanks for yet another example of "I can't be bothered to actually read. Just willy nilly asserting something has to suffice".

    I think you understood him wrong. he saw that you indeed used that flag in all fio calls. therefore he (and me too) thinks your cached results are actually not cached for fio anyway. simply because fio bypasses the cache, no matter if you deactivated it via hdparm or not ;-)

    so that would be a reason, why the fio result are that consistent - the direct=1 makes it that way.

    Thank you for your more detail explanation. I hope jsg could understand my concern above.

    Thanked by 2stevewatson301 adly

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  • Guys, DC and AC both have their use. They are simultaneously both the right and wrong approach for the task.

    Thanked by 1jsg

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  • @jsg said:

    • Said OP explained that AWS can be trusted because they would not lie to large corporate customers

    Said OP is me, in case anyone was wondering.

    I guess Docker and the Linux kernel were also lying? And did you forget about the fact that the kernel limits wouldn't consider the cache as the operating system would slow down all I/O requests from that process?

  • jsgjsg Member, Resident Benchmarker
    edited September 14

    @Falzo said:
    I think you understood him wrong.

    Maybe. I'm human so that can happen.

    he saw that you indeed used that flag in all fio calls. therefore he (and me too) thinks your cached results are actually not cached for fio anyway. simply because fio bypasses the cache, no matter if you deactivated it via hdparm or not ;-)

    As for the matter: I ran all, vpsbench, fio, and dd in sync mode. One time (top half) with linux cache not disabled, and one time with linux disk cache disabled (lower half).

    One major reason for that was to find out whether linux really disables caching when asked and whether it's completely disabling them.

    would you provide your newer version of vpsbench? I'd be interested in running it again on my dedi with the regular HDDs. any details on what you changed?

    Right now my answer is "highly likely not. highly likely I won't publish/share any newer versions". I'll probably be willing though to sometimes later provide it to a select few on the condition that they do not give it to others. (Hit someone who only had good intentions and invested a ton of work and time for a community often enough and nastily enough and it'll make him think ...). You are btw among the few whom I would consider to provide newer versions to.

    on another note, the IOps shown for the spindle are to high anyway, it should be max 200 even for a very fast one. this suggests that the overall size of 128MB is too small for a reliable measurement and indeed hitting the HDDs cache only.

    Yes and no. You see, I tasked vpsbench, fio, and dd to do the same job with the same drive and that's not somehow bent or unfair. But there are practical factors too. The Firecudas on-board cache is 8 GB and trust me, doing all the tests I did with a test size of say 10 GB would have taken an eternity.
    Whatever, the result values I show above are exactly what the tests achieved.

    the write speeds seem quite slow but could actually make sense considering that it's a product of iops*bs so 4.9MB/s at 64k blocksize result in somewhat 80 IO per second (which again seems reasonable for a spindle.

    that still leaves me wondering why the difference between write and read speed is that large. and especially that random reads regularly achieve higher speeds than sequential ones even on HDD will never make sense to me. it feels a bit like if your read routine suffers from parallelism or something like that, while writes do not. just sayin' ... unprofessional personal opinion that is.

    Oh, I'm wondering about quite a few things too, but I can't offer more than an educated guess without investing a lot more work and doing much more specific and elaborate and extensive testing. It seems that disabling this or that cache (there are quite a few involved at different levels) actually just disables write caching. I've also seen built-in caches that are entirely different again and never cache one or the other, either read or write.

    I'm afraid that no matter my good will I have to stop at some point trying to find answers to those riddles. Simple reason: vpsbench is not particularly a disk benchmark but a VPS benchmark. the disks are just one element of the mix. At the moment for example I'm working on bringing in some OpenSSL routines because many are interested in that.
    But I'm willing to help you to some degree albeit sadly a limited one.

    The problem with democracy is that by definition > 85% of the voters are not particularly intelligent.

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