Leap Second Bug Causes Crashes 230
An anonymous reader writes in with a Wired story about the problems caused by the leap second last night. "Reddit, Mozilla, and possibly many other web outfits experienced brief technical problems on Saturday evening, when software underpinning their online operations choked on the “leap second” that was added to the world’s atomic clocks. On Saturday, at midnight Greenwich Mean Time, as June turned into July, the Earth’s official time keepers held their clocks back by a single second in order to keep them in sync with the planet’s daily rotation, and according to reports from across the web, some of the net’s fundamental software platforms — including the Linux operating system and the Java application platform — were unable to cope with the extra second."
All of my servers were fine (Score:5, Insightful)
And I didn't do anything special, just kept their software up-to-date.
Our Red Hat servers had no issues at all (Score:5, Insightful)
I'm uncertain why these reports keeps referring to some monolithic "Linux" that is supposed to have had issues - Red Hat's the biggest Linux vendor, and certainly their "Linux" handled it just fine.
What distros had issues?
FUD? (Score:2, Insightful)
Re:Why now? (Score:5, Insightful)
and above all it should not be changed to accomodate fluctuations in the orbit of a rock circling an arbitrary star.
That is precisely the point of keeping track of the time of day, or day of the year.
time of day is an arbitrary number whose main utility lies in it being composed of predictable periods and divided into homogenous units.
You do not need a complex system like date time comprised of minutes hours, seconds, months, weeks, and years if you just want to measure time in a convient homogenous unit then define a time-zero, and just count milliseconds from that to whatever arbitrary distance into the past and future you want from that. Measure it kilo-seconds, mega-seconds, giga-seconds... etc.
The entire point of date/time is because we do in fact care a lot about how that "arbitrary counter" lines up with when we will be awake or asleep or eating at various points -- that's what makes it useful.
What we should have is what I've described above, time-zero and a counter. And translations from that to localized date time should be handled by a library.
Re:All of my servers were fine (Score:5, Insightful)
And I didn't do anything special, just kept their software up-to-date.
That's a nice ideal, but the reality is that many up-to-date "stable" distribution releases are still using kernels which are susceptible the leap second problem (and haven't had the patch back-ported to them). Ubuntu 8.04 LTS server is supposed to be supported until April 2013, and on my (updated!) system,
# uname -r
2.6.24-28-server
I like the idea of stable releases, but this is a glaring problem with the entire idea. Everyone extolls the wondrous virtues of package managers for Linux-based systems, but the dirty secret is that unless you stay bleeding-edge (which is usually the opposite of "server"), you'd better be happy with the 4-year old version of Apache, PHP, MySQL, and the Linux kernel you're running. Sure, it's possible to manually download and install packages from a newer release (assuming you can get past the dependency hell usually associated with it). Sure, it's possible to try and splice in (or "pin" packages using Debian parlance) from a newer repository. Sure, it's possible to install from source, compiling and installing everything by hand. But once you do any of these you've given up 90% of what makes the package manager useful and are just asking for dependency problems in the future.
And, all that aside, do you even know if the patch released to fix this problem is included in your distribution-released kernel? If you're not rolling your own kernel it can be nigh to impossible to know what's included and what's not -- in that case it doesn't even matter if it's up-to-date.
Re:FUD? (Score:2, Insightful)
I seem to recall Microsoft suffering from some leap year bugs. Boy, the Slashdot comments section lit up about how even a kindergarten programmer would catch the mistake and how it's indicative of the software quality coming out of Microsoft. Now that Linux hit the same type of hurdle, we're all of a sudden being very nuanced about the definition of code quality? Typical.
the difference being this bug was patched already it only affected systems the were not kept up to date. Microsoft however did not patch or fix their software until after the problem had already occurred. the fault lies not in Linux here it lays with system/server admins not updating their servers. where with Microsoft case it was their direct fault for not handeling a well known date issue. where with the Linux bug no one had heard of leap seconds until yesterday yet it did have a patch already out there not their fault or problem.
Re:I always thought leap seconds were stupid (Score:5, Insightful)
> Why not bundle them and apply them every 10 or 20 years?
The problem we have here is that leap seconds are rare. Things that are common are tested for, and quickly found if broken. Having something which only happens every 20 years is a recipee for disaster every 20 years.
My view is that NTP is at fault, because the 61th second is a brittle way to handle it. NTP should use the same method as google for smearing the leap second out over fx an hour: http://googleblog.blogspot.dk/2011/09/time-technology-and-leaping-seconds.html [blogspot.dk]
Re:I agree... (Score:4, Insightful)
When NTP knows that a leap second is to be added, it (on Linux at least) sets a flag in the kernel to say that at 23:59:59, please continue to 23:59:60 before going to 00:00:00. This is set by NTP anytime on the day that the leap second is due to be implemented, hence why a server running NTP on Linux would know that TODAY a leap second is due (cause they should always be posted at the 23:59:59 cross-over)