By webserver I meant the box not the daemon running on it. I wasn't
trying to give everyone a lesson on TCP, I was just implying that the
original post about the problem being based on a location were probably
false. I'm still curious if it was the entire site or just a few of the
servers in a load-balanced pool
Re: [outages] FB down?
Jeremy Chadwick
to:
outages
04/23/10 07:48 PM
Sent by:
<outages-bounces at outages.org>
On Fri, Apr 23, 2010 at 07:08:14PM -0400, Keegan.Holley at sungard.com wrote:
> Correct me if I'm wrong but aren't RST's sent by the TCP stack in the
> webserver? If you are recieving them it would imply that the network
> connection is fine, but you were sent to a server that is having issues.
> WIth the amount of traffic they recieve I would assume they use some
sort
> of load balancing method. Try clearing your DNS cache and closing your
> browser and trying again.
RSTs are sent by the OS (not the "webserver"; there is no TCP stack
inside a webserver) when the underlying userland application calls
close(2) on the descriptor (socket), the process exits, or otherwise
aborts/crashes in some way thus freeing the descriptor that handles the
network I/O. Facebook's predominantly using Linux[1] which is why I
describe the above model.
Given Facebook's complexity, who knows what the problem was. Load
balancer or layer 7 filter/re-writer (think F5) issues? Back-end server
problems? Software misconfiguration? Doing burn-outs in an AMC Pacer
by sticking with PHP[2]? Some developer deciding to just roll something
out in the middle of the day (as is quite common with social networking
sites these days)? We'll probably never know.
If I had a nickel for every time I've seen FB's environment behave
erratically (easy to confirm with curl), close sockets abruptly, time
out during HTTP transactions, I'd own a series of small islands by now.
[1]:
http://www.infoq.com/presentations/Facebook-Software-Stack [2]:
http://developers.facebook.com/blog/post/358 --
| Jeremy Chadwick jdc at parodius.com |
| Parodius Networking http://www.parodius.com/ |
| UNIX Systems Administrator Mountain View, CA, USA |
| Making life hard for others since 1977. PGP: 4BD6C0CB |
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> [outages] FB down?
>
> Franck Martin
> to:
> outages
> 04/23/10 06:12 PM
>
>
> Sent by:
> <outages-bounces at outages.org>
>
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> FB is down from Fiji: the connection to the server was reset
>
> Franck Martin
> http://www.avonsys.com/
> http://www.facebook.com/Avonsys
> twitter: FranckMartin Avonsys
>
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