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So what happened to the HN server?

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Re: So what happened to the HN server?

#91

Post by tferris »

jules wrote: post #86
tferris wrote: post #21

Saturday, I thought: "This guy (PG) is really brave, everybody is nowadays using virtualized server environments on mulit-core machines and PG just gets some bare metal and puts his app on one core and one thread. WTF, this guy is a genius, single-threaded apps on bare metal FTW, this is so great and I am doing this too." After seeing this thing down for several hours -- and Google hate downtimes, they punish you ins…

Virtual servers vs dedicated servers has not much to do with reliability. Both go down. What you want to minimize the risk of downtime is redundancy, e.g. hot fail-over.

what's the best way to have hot fail over?

Re: So what happened to the HN server?

#93

Post by jules »

jgrahamc wrote: post #88
jules wrote: post #79

Earlier quoted context omitted.

That doesn't really have much to do with the expired link issue. That issue exists because the targets of links are stored as closures on the server. What you want is to serialize those closures into the URL itself, instead of letting the URL be a pointer to a closure stored on the server. In traditional web applications, you'd have to do that serialization manually (although if you've never used such a closure based…

"The problem used to be much worse, but then PG did this transformation manually for the important subset of the site (most importantly for links to the comments section -- these links no longer expire)." I don't think this is strictly true. The comments and reply links simply link to a normal (non-closure) URL on the site and the page is generated from that URL in the normal manner.

I don't understand the disagreement...isn't that the same thing I said? IIRC it used to be the case that all links could expire, then he did this transformation from closures stored on the server to closures manually serialized in the URLs (which results in a normal URL as you say). What I'm describing is how a web framework could do that automatically, which means you get the behavior and expressiveness of closures without the link expired issue. Though I can see that the explanation isn't very clear, but I don't know how to make it more clear. Edit: don't downvote him people, it is a perfectly fine comment.

Re: So what happened to the HN server?

#94

Post by Udo »

dfc wrote: post #90
Udo wrote: post #75

Earlier quoted context omitted.

It's curious, isn't it, that we still have "Home" pages. For a while there, Google Reader was my starting point, but nowadays I find myself starting off from HN. This must be what Facebook feels like to normal people, but without the insidious stalking and the dreaded obligations that come from surveillance features like "X is online NOW, you have to interact with him/her!" and "X has seen this (but has neither liked…

Normal people? I just vomited a little. Thanks for ruining breakfast.

You're very welcome. And I allege you know that's not how I meant it. Do you really want to assert that the subject matters at HN are part of mainstream culture? I do believe that IT people tend to use the internet differently, this is not an elitist observation in case it came across as such. It's just different.

Re: So what happened to the HN server?

#95

Post by jules »

tferris wrote: post #91
jules wrote: post #86

Earlier quoted context omitted.

Virtual servers vs dedicated servers has not much to do with reliability. Both go down. What you want to minimize the risk of downtime is redundancy, e.g. hot fail-over.

what's the best way to have hot fail over?

That very much depends on the scale you're at and the database that you use. If your scale is such that you could comfortably run on 1 machine (as it is for 99% of sites), it's probably sufficient to rely on your database to handle the replication. For example for postgres: http://www.postgresql.org/docs/devel/static/high-availabilit...

Then to utilize this you want a load balancer in front that's unlikely to fail and if it fails can be restarted rapidly. This load balancer should send requests to the other server as soon as one has failed. The other option is DNS failover, which can work but has different trade-offs.

One thing that this does not protect you against is repeatable failure due to a software bug. If a request comes in that happens to crash one of your servers, load will be quickly switched to the other. But the user that cause the original server to crash might refresh his page because he didn't get any response back, which also sends the problematic request to the other server, and might crash that one too. These kind of problems are very hard to deal with (if the requests don't come from humans but from programs that automatically retry their request to other servers when they don't get a response it's even worse: a single bad request can bring an entire cluster down in seconds).

Paradoxically sometimes measures to improve availability can cause availability to go down. If you make your architecture more complicated you introduce more opportunities for failure, especially due to bugs. If you have multiple servers in a pipeline, for example a load balancer and then the real servers which in turn talk to the database servers, that can also cause your likelihood to fail due to hardware to increase. If your pipeline depth is three, then the chance that you have a hardware failure is about three times as big compared to when you had a pipeline depth of one. You want to minimize the depth and maximize the width of the pipeline.

So you should ask yourself whether it's worth it, especially when you're small. Many of the successful sites had or still have a lot of downtime. Maybe it's better to minimize the duration of downtime with fast restarts rather than trying to lower the probability of downtime.

Re: So what happened to the HN server?

#96

Post by dfc »

Udo wrote: post #94
dfc wrote: post #90

Earlier quoted context omitted.

Normal people? I just vomited a little. Thanks for ruining breakfast.

You're very welcome. And I allege you know that's not how I meant it. Do you really want to assert that the subject matters at HN are part of mainstream culture? I do believe that IT people tend to use the internet differently, this is not an elitist observation in case it came across as such. It's just different.

I have a friend who is big into fantasy sports (blue collar job: construction). The first thing he does when he sits down in front of the computer is that he checks whatever roster he is managing at the time. Is he not "normal"?

Re: So what happened to the HN server?

#97

Post by Surio »

dfc wrote: post #89
lifeisstillgood wrote: post #69

I have only one portal onto the Internet - this site. I check it first thing and last thing, and when it was down today I had a weird epiphany - I did not mind. HN is not a service, its not a startup trying to get mindshare - its a (luvvie alert) community - and one where the downtime had a known and obvious cause and did not matter - rtm would fix it, I would catch up, I knew this thread would exist and I would stil…

I am not familiar with "luvvie alert" ?

Oh British English, how much I love you..... Let me count the ways! [http://en.wikipedia.org/wiki/Let_Me_Count_the_Ways] ;-)

http://oxforddictionaries.com/definition/english/luvvy

http://tvtropes.org/pmwiki/pmwiki.php/Main/Luvvies

Re: So what happened to the HN server?

#98

Post by Udo »

dfc wrote: post #96
Udo wrote: post #94

Earlier quoted context omitted.

You're very welcome. And I allege you know that's not how I meant it. Do you really want to assert that the subject matters at HN are part of mainstream culture? I do believe that IT people tend to use the internet differently, this is not an elitist observation in case it came across as such. It's just different.

I have a friend who is big into fantasy sports (blue collar job: construction). The first thing he does when he sits down in front of the computer is that he checks whatever roster he is managing at the time. Is he not "normal"?

I get the feeling that you choose to misunderstand. If there is anything I can add to this line of discussion I will gladly do it, but I have to admit I'm a bit lost as to what your problem is here.

Re: So what happened to the HN server?

#99

Post by dfc »

Udo wrote: post #98
dfc wrote: post #96

Earlier quoted context omitted.

I have a friend who is big into fantasy sports (blue collar job: construction). The first thing he does when he sits down in front of the computer is that he checks whatever roster he is managing at the time. Is he not "normal"?

I get the feeling that you choose to misunderstand. If there is anything I can add to this line of discussion I will gladly do it, but I have to admit I'm a bit lost as to what your problem is here.

I didn't choose your words.

Re: So what happened to the HN server?

#100

Post by ralph »

kyro wrote: post #47

PG wasn't aware that PetSmart closes an hour earlier on Sundays, so he was forced to wait till opening this morning to get the additional hamsters needed to keep this place running.

I remember when this would have been considered noise here; now it's the top comment.
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