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Іван Франко

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19 June 2015


Selected projects See all »

Banalize: Bash static code analyzerDBIx::Report::ExcelShell settings, AKA dotfilesNagios Monitoring for Couchbase serverNagira: RESTful API for NagiosStartpack for Github pages developmentWeb iPhoto

Travel Blog Витрішки »

Україномовний блог Витрішки - блог про все, крім роботи. Цикл статей "Літо на півночі Японії" з цього блогу тепер опублікований у Витрішках

Computer Blog All posts »

iPhoto and files permission Is MacOSX 10.9 == MacOS 9.x? Running Chef roles from Capistrano und Capiche Github & Jekyll: Speeding up Jekyll siteGithub & Jekyll: More experience with Jekyll and setup changesBuild new hosts with Capistrano and Chef Request Tracker: More about custom CSS for RT4Ruby 2 test drive Nagira v0.2.5 release It's UNIX my dear Watson

Slides See all »

Nagira @TLUG, 2012Rspec and Guard


Ярило Yarylo, Jarilo me @ github me @ CPAN Dmytro (CV)

Can one little second kill your servers?

Actually — yes.

Early Saturday morning Japan time most of the servers in the company where I work now started to act. CPU usage spiked to 100-200% while no load was actually hitting the servers.
Mysql on restart used again insane amount of CPU. At the same time, servers were quite responsive and acting like normal.

After some time later reports started to appear in Google search… Reports were talking about … leap second

At the mid-night GMT time on Jun 30, 2012 extra second was added — leap second. NTP supposed to have been picked up that small change, but it did not. Most of the Linux servers’ CPUs went into timeless cycle: check flag (‘leap second’ flag in NTP protocol), set flag, check flag, reset flag …

The funniest thing about all this story is sequence of commands you’d have to run to fix the issue:

        ntp stop
        ntpdate ntp.pool.org
        ntp start

Or even this (!!) :

        ntp stop
        date -s "`date`"
        ntp start

дмитро ковальов
dmytro @ github