A couple years ago we had issues caused by a 0 (zero) leap second, which honestly I couldn’t find documented anywhere but hacker news! Something about the system expects a leap second every 17 years and if it doesn’t get one it’s more troublesome than the 0 leap second.<p><a href="https://news.ycombinator.com/item?id=27944776">https://news.ycombinator.com/item?id=27944776</a>
One of the more unseen side-effects of this particular bug back in 2012 was datacenter internal temperatures spiking by ~5℃ due to the increased CPU usage iirc.
We've already discussed the Leap Smear, where clocks run 0.0012% slower for a day.<p><a href="https://news.ycombinator.com/item?id=28047714">https://news.ycombinator.com/item?id=28047714</a><p><a href="https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=leap%20smear&sort=byDate&type=story" rel="nofollow">https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...</a>
I recall this hitting our startup’s various MySQL Linux servers in 2012.<p>They were slow/maxed out for a while till we figured it out. The DBA rebooted a few but didn’t know why and it kept cropping up on others; I drilled into root cause with some google-fu.<p>Not mentioned in the article is that I think this issue occurred again in 2015. I don’t recall if it hit us because we hadn’t patched/upgraded some servers since 2012 (!) and had just relied on resetting the clock/rebooting, or there were more Linux bugs (see LWN below).<p>Good technical writeup from Linux weekly news: <a href="https://lwn.net/Articles/504744/" rel="nofollow">https://lwn.net/Articles/504744/</a><p>And more on Linux patching in 2015:
<a href="https://lwn.net/Articles/648313/" rel="nofollow">https://lwn.net/Articles/648313/</a><p>IANA canonical list of leap seconds:
<a href="https://data.iana.org/time-zones/tzdb-2018a/leap-seconds.list" rel="nofollow">https://data.iana.org/time-zones/tzdb-2018a/leap-seconds.lis...</a>
> Hany explains: “Due to physics, at certain times of the year, the Earth moves faster along its orbit than others. How do we base time off of this, then?”<p>Sorry, but no. This is so wrong I don't know where to start.