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Behind the Scenes at Hotmail

mallumax writes "ACM Queue interviews Hotmail engineer Phil Smoot on how they manage more than 10,000 servers spread around the globe. Between them, they process billions of emails per day and are overseen by hundreds of administrators. To do that they have returned to the command line. From the article: 'Our operations group never wants to rely on any sort of user interface. Everything has to be scriptable and run from some sort of command line'. The overriding philosophy seems to be KISS. Also: tape backups are out and spam levels have stabilized."

31 of 292 comments (clear)

  1. KISS my hotmail body by digitaldc · · Score: 4, Funny

    The overriding philosophy seems to be KISS.

    Don't try to tell me that the guys at Hotmail only want to Rock & Roll all night and party every day?!?

    --
    He who knows best knows how little he knows. - Thomas Jefferson
    1. Re:KISS my hotmail body by DJ_Goldfingerz · · Score: 5, Funny

      I read you subject as "KISS my hotmale body".

  2. UNIX? by IAmTheDave · · Score: 4, Interesting

    If I recall correctly, wasn't Hotmail originally run on UNIX boxes?

    --
    Excuse my speling.
    Making The Bar Project
    1. Re:UNIX? by Kraegar · · Score: 5, Informative
      It used to be on FreeBSD w/Apache, now it runs on Windows w/IIS. It's not exchange based.

      Read about it

    2. Re:UNIX? by Amoeba · · Score: 5, Informative

      Yes. Hotmail was originally run on clusters of E3500 and E4500's running Solaris 2.5.1. After they got bought by Microsoft, a major initiative to migrate all boxes to Windows was undertaken in 2000. Hotmail has been 99.9% Windows for over 3 years now. The remaining 0.1% are some legacy solaris boxes used to handle backups for clusters... and even they are being phased out slowly.

      --Amoeba (who no longer works there)

      --
      Do not taunt Happy-Fun Ball
    3. Re:UNIX? by TheLink · · Score: 3, Interesting

      Did Hotmail have a higher server (or hardware cost) to subscriber ratio after they migrated to windows?

      --
    4. Re:UNIX? by enantiodromia · · Score: 5, Informative

      This is only half true. The _front end_ runs on Windows with IIS. The _back end_, where the email data is stored (the User Stores), are Solaris. The front end machines dont mean much. If one or twenty go down, there are tons more to take their place. They are simply removed from the load balancing and marked as "admin plz fix this some day". The back end machines however, are super critical, as each user lives one one, and only one, user store. That machine goes down, and hundreds of thousands, to millions, of Hotmail users cant get to their mail. And thats why those machines run Solaris.

  3. Better subject... by pegr · · Score: 5, Funny

    "Between them, they process billions of emails per day and are overseen by hundreds of administrators."
     
    And how does the NSA process all that email? Now THAT would be an interesting technical challenge!

  4. Does anyone know... by ehaggis · · Score: 4, Funny

    What OS it runs on and which web server? I am not trying to be funny.

    --
    One ring to bind them - should probably have more fiber and less rings in their diet.
  5. Fairly Impressive by eldavojohn · · Score: 4, Interesting
    I don't know about everyone else but this article was shocking to me.

    Not only are the questions well picked but the some of the answers are quite interesting. For instance Phil on scalability:
    The problems are those of basic client-server programming--that is, figuring out the browser/http/server data-access patterns and optimizing the protocols, extending these protocols as new functionality is introduced, and ensuring that these protocols work across geo-distributed data centers when the speed of light becomes a factor. Designing applications with built-in redundancy so that they are resilient to abuse is also a challenge.
    Before reading this article, I always had hotmail pegged as a hacked together e-mail system less organized than a monkey sh*tfight but if Phil speaks the truth, I've underestimated them. They're a hacked togethor server mess with a lot of effort put into staying afloat--and they have been doing well for a long time.

    I guess I've always taken my free Hotmail account for granted.
    --
    My work here is dung.
    1. Re:Fairly Impressive by mekkab · · Score: 3, Informative

      Not only are the questions well picked

      The interviewer is ACM Queue editorial baord member Ben Fried, who is the managing director of Morgan Stanley's worldwide IT deptartment.

      --
      In the future, I would want to not be isolated from my friends in the Space Station.
  6. Spam improvment, but not perfect yet by saskboy · · Score: 3, Interesting

    I used to get about 35 spam a day in my primary hotmail account that I'd had since 1997. Now it gets about 4 a day so things have improved, but my biggest concern about Hotmail is that its virus scanning is horrible. There have been several times when it would have let me download a virus attachment, or allowed multiple obvious virus messages through. They've switched to Trend from McAfee, but I think the problem still remains.

    --
    Saskboy's blog is good. 9 out of 10 dentists agree.
  7. High level of QC! by Anonymous Coward · · Score: 5, Informative

    From the article:
    Hotmail relies on less than 100 system administrators to manage it all.

    From the summary:
    Between them, they process billions of emails per day and are overseen by hundreds of administrators.

    Brought to you by the high quality control here at /.

  8. Command line by Anonymous Coward · · Score: 3, Insightful

    > To do that they have returned to the command line.

    Absolutely.

    I'm currently in the process of trying to change our company culture away from legacy GUI tools and toward command-line tools.

    Scriptability is a highly under-rated goal. I'm not against GUI tools -- but they need to be built on top of scriptable utilities.

  9. Re:I wonder.... by daikokatana · · Score: 4, Funny
    ..who they call for support? :-)

    Ghostbusters?

    --
    http://jcsnippets.atspace.com/ - a collection of Java & C# snippets
  10. Interacting without any sort of user interface by Phat_Tony · · Score: 4, Funny
    "they have returned to the command line. From the article: 'Our operations group never wants to rely on any sort of user interface"

    I always thought that the command line was a user interface. You know, interfacing between a user and a computer.

    It's hard to picture using a computer without any sort of user interface. I'm pretty sure that, in order to call it "using" a computer, some sort of interface must exist, be it keyboard mouse and monitor, binary switch, light gun, real gun, neural link, telekinesis, or whatever. Otherwise, you're not using it, are you?

    On the other hand, maybe the article is correct- a lot of operations group probably don't want to use "any sort of user interface" to communicate with their computers. They want to be sitting on a beach in tahiti drinking daiquiris, thousands of miles away from the computers they're supposed to maintain.

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    Can anyone tell me how to set my sig on Slashdot?
  11. Oh, come on yourself. by ScentCone · · Score: 3, Insightful

    It's like one commercial after another. 'See how great we are!!'

    Right... it's always more interesting to read article after article about only unsuccessful operations run by people who aren't proud of what they do, and don't face huge, global challenges.

    You're cranky because it's MS. If exactly the same article ran, substituting "gmail" and "google" for all of the other names, you'd say, "cool!"

    --
    Don't disappoint your bird dog. Go to the range.
  12. From the immortal words of Henry Spencer by hackstraw · · Score: 5, Insightful


    "Those who don't understand UNIX are doomed to reinvent it, poorly."

    From the article and elaborating on the /. summary (It has a print version that consolidates the 4 pages together if you want):

    Q: Are there scaling reasons to think about the benefits of a command line for managing over a GUI, or are there other things to think about?

    A: Our operations group never wants to rely on any sort of user interface. Everything has to be scriptable and run from some sort of command line. That's the only way you're going to be able to execute scripts and gather the results over thousands of machines.

    Also, we all remember the scaling issues that MS had when they took over hotmail and initially tried to switch from freebsd to Windows.

    MS had to port over cron jobs because its not something that is installed and used by default under windows like UNIX. They had to rewrite the "inefficient" perl code that ran fine on FreeBSD to C++. They had to redo the memory allocation to prevent memory leaks in the new C++ code. Read about it from the goat's mouth http://www.microsoft.com/technet/interopmigration/ case/hotmail/default.mspx.

    I can't wait until FreeBSD and other inferior OSes get tools to find memory leaks. One day....

    (That last line was sarcasm and not a flame).

  13. Coral Cache by OctaneZ · · Score: 3, Informative

    Looks like the site is down, it is however there is, however, a Coral Cache copy.

  14. Re:stabilised... by the+chao+goes+mu · · Score: 4, Funny

    Stabilized at 100% of bandwidth.

    --
    Boys from the City. Not yet caught by the Whirlwind of Progress. Feed soda pop to the thirsty pigs.
  15. F**Kin Speak English ! by CmdrGravy · · Score: 4, Insightful

    Why does he keep mistaking the word "use" for the word "leverage" ? The only possible advantage I can see in substituting the word "leverage" is that it sort of implies they are making the best use of these tools that they can in which case you would think that most people would have already assumed they are not making the worst possible use they could of the tools and it's interesting that the author feels it necessary to make that distinction.

    1. Re:F**Kin Speak English ! by kotj.mf · · Score: 4, Funny
      Why does he keep mistaking the word "use" for the word "leverage"?

      Because his team leverages best-of-breed systems to utilize the synergistic effects of the paradigm shift in relationships among stakeholders and the knowledge infrastructure, silly.

      --
      hang brain.
  16. Hundreds of administrators by Iphtashu+Fitz · · Score: 4, Interesting

    more than 10,000 servers spread around the globe ... are overseen by hundreds of administrators.

    Heh. I used to work at Akamai which provides content delivery services for many of the biggest sites on the web. They have somewhere over 15,000 servers that are managed by tens of administrators, not hundreds. In fact, a typical NOCC (yes, 2 'C's for Akamai) shift at Akamai is only staffed by 8 or so people, with only a couple of senior level admins on call. And they're delivering all sorts of web-based content, including streaming, not just e-mail.
    But then Akamai runs them all on linux, whereas I belive Hotmail is all Windows based. You do the math.

    1. Re:Hundreds of administrators by SpotTheCat · · Score: 3, Informative

      From TFA:
      What's interesting is that despite this enormous amount of traffic, Hotmail relies on less than 100 system administrators to manage it all.

    2. Re:Hundreds of administrators by Iphtashu+Fitz · · Score: 4, Insightful

      I think running a mail server is a bit more complicated than a webserver or a streaming server for video

      It sounds to me like you don't understand what it is that Akamai does. They're not just running web & streaming servers on their 15k machines. They're distributing content in real time in a way thtat vastly improves user access all around the world. You may have heard when Victorias Secret held their first video-streaming lingerie show. Well their servers couldn't handle the load because of all the people trying to watch it. They became an Akamai customer, and Akamai was able to redistribute their streams in real-time all over the globe. To be able to take video (or just web content) from a single source and distribute it quickly and efficiently to thousands of distributed users in real-time is a huge undertaking. Akamai has some very impressive technology to be able to do this.

      I'm not saying that running a mail service like Hotmail is a piece of cake, but I do think that what Akamai does is a lot more difficult and impressive when you think about it. If Akamai's distributed environment were to drop off the net then you probably wouldn't be able to access any of the on-line services of most of their customers. (And that's just a small subset of their customer base) The ability to keep websites like those of Microsoft, eBay, Fed Ex, Red Hat, etc. all highly responsive to end users is not a simple feat by any stretch of the imagination.

  17. Hotmail was next to my cage at by wsanders · · Score: 4, Funny

    AT first, it was BSD running on a bunch of identical custom-made sub-1U servers. But No! Then it was replaced by windows boxes . . . racks and racks of 99c Fry's keyboards velcroed to the backs and fronts of racks, with miles of small-gauge track, upon which ran diabolical steam-powered robots, each with a single arm and with fingers at the end, forever fixed at the precise spacing to stab the keyboards' CTRL-ALT-DEL keys. Noisily the robots rumbled back and forth on their appointed rounds . . .

    --
    Give a man a fish and you have fed him for today. Teach a man to fish, and he'll say "WHERE'S MY FISH, YOU IDIOT?"
  18. Paul Graham on the importance of tools by mi · · Score: 3, Insightful
    Hotmail's suckiness is a management problem, not a technology problem. The technology is there, but [...]
    Paul Graham argues convincingly, that a tool can make all the difference (he advocates Lisp).

    He submits, of course, that any program can be written in any reasonable language -- for they all are, after all Turing machine's equivalents. But the quality of the tools can make a difference between a feature being added next week and not at all.

    If Hotmail's admins are back to command line and scripting anyway, maybe, they should've stuck with FreeBSD.

    Look at how quickly Google is rolling new things out -- their platform allows them to.

    --
    In Soviet Washington the swamp drains you.
  19. This is why Google is on top now by esconsult1 · · Score: 3, Interesting
    After reading the article, it seems that a they did not think out a really scalable platform to run their services and apps. So over time, it became a huge mashup of servers and services. Heck, they can't even properly map the production environment to a small development set.

    Compared to Google clusters, they seem to be light years behind. As a software developer, I can tell you that the key to rolling out applications quickly, is to have a decent framework in place. Whatever that framework might be (from shell scripts to java monstrosities), once its in place, developing apps on top of it are easy. Similarly a well thought out app execution environment is golden.

    If you ever check out Google's MapReduce, you'll see what I mean. It's just so well thought out and so elegant, that its easy to believe that they can scale outwards forever. You'd not be too far off if you thought that Microsoft were rethinking their whole production environment to compete with Google.

    There's no way that Microsoft can quickly and easily roll out vast new applications that scale, because that whole clustering framework is completely opposite to what Windows provides.

  20. Hotmail is so irrelevant by bill_kress · · Score: 3, Interesting

    I was a strong hotmail user before Microsoft took it down, uh, I mean took it over.

    It was a great service! One of the first, and probably the best.

    Microsoft took it over and there was no advancement or innovation for years (a decade?). Spam ate up my tiny inbox while Microsoft just threw MSN graphics all over the place.

    When Gmail came out, I gave it a try. It was everything Hotmail could have been years ago if it hadn't been bought by MS! (Well, it COULD have been out of business, so I've got to give them that I suppose).

    They forced Microsoft to pay a little attention to features. They gave out a little more storage and started blocking some spam, but it was too little too late.

    In order to write this I decided to visit my hotmail inbox, I haven't been there for a while. 136 emails, and 43 have been detected as junk. They are ALL junk--A party invite from "heather", a Cola Quiz, etc. 136 undetected junk emails out of 179.

    And even at that, they still only give 1/8 the amount of storage that Google does.

    Crap, on top of that I just looked at a spam with pictures in it and it didn't auto-block them like Google does. Now I'm probably infected.

    Thanks Microsoft!

    From,

    The guy who used to argue the advantages of Microsoft to the Unix admins...

    1. Re:Hotmail is so irrelevant by nighty5 · · Score: 3, Interesting

      I've agree with mostly what you've said, but I'd say it was Yahoo that pushed Hotmail's innovation button, and not Gmail.

      Gmail didn't appear until much later on, but Yahoo were creating some fantastic portal features.

      I have a Gamil, Yahoo & Hotmail accounts, but prefer to give out my Hotmail account for "free offers" and other junk, its a junkbox.

      However Gmail & Yahoo are both solid email solutions, and as you say, Gmail fairs better than all of them in the spam war.

      Gmail; From a geek perspective, I admire them for creating key mappings that mimick those of vi/vim.

      There is features present in Yahoo I'd love to see in Gmail:
      * Setup up one-time (or temporary) email addresses that are binded to your email address.
      * A decent calendar that can sync to iCal and Sunbird. (I don't think Yahoo have this yet)
      * Events management, setup birthday reminders and the like.
      * A virtual notepad that you can scribble down notes
      * Sharing your calender, its private by default.
      * Check number of new messages without logging in or providing credentials (uses a cookie)

      Yahoo is awesome, if you havent tried out their web portal, take a look. Its very impressive.