Leap Second today at 00:00 UTC - Bruised by past mistakes, tech firms brace for impact
Bruised by past mistakes, tech firms brace for 'leap
second'
By Tim Hornyak
IDG News Service | Jun 30, 2015 12:10 AM PT
Just before the stroke of midnight Tuesday Coordinated
Universal Time (UTC), computerized clocks around the world will pause for a
moment to squeeze in an extra second.
The leap second, as it’s called, is needed to keep UTC in
line with solar time. The two get out of whack due to changes in the earth’s
rotation, and 25 leap seconds have been added to clocks since 1971. Network
Time Protocol (NTP) helps regulate the official time among Internet servers,
keeping it in sync with UTC.
But the last leap second in 2012 took some IT companies
and other firms by surprise, and caused websites including LinkedIn and Reddit,
as well as Qantas’ passenger reservation system, to crash. The problems
involved unpatched Linux OS kernels, Hadoop instances, Cassandra and MySQL
databases and Java-based programs.
Linux systems in particular were the focus of discussion
after the 2012 leap second, as the bug caused everything from slowdowns in
performance to overactive systems that led to CPU locks, Ron Pacheco, director of
product management at Red Hat’s Platforms Business Unit, said via email.
This time around, however, vendors say they are better
prepared.
“Our small-scale tests are promising, and we’ll be
watching during the event to quickly respond to any unforeseen issues that may
arise,” a spokeswoman for Reddit said via email.
A spokeswoman for LinkedIn, meanwhile, said clock
adjustments are being made to prevent any problems.
Qantas, one of the first major companies affected by the
leap second in 2012, was hit by computer outages that delayed flights due to
the effect of the Linux bug on the Amadeus reservation system, produced by
Spain’s Amadeus IT Group. The system is used by dozens of airlines around the
world.
“We have sought and received assurances from Amadeus that
they have taken action to make sure that the same problem does not happen again
this year, and we’re confident that it won’t,” a Qantas spokeswoman said via
email. Amadeus did not respond to requests for more information.
There are several methods of dealing with the leap
second. Google, for instance, implements a “smear window” centered on the leap
second. To ensure that its NTP servers are in sync with the extra second, they
are slowed, or “smeared,” by about 14 parts per million.
“Twenty hours later, the entire leap second has been
added and we are back in sync with non-smeared time,” Google engineers Noah
Maxwell and Michael Rothwell wrote in a blog post last month.
Another approach is to have servers simply count the 60th
second twice at 23:59:59 UTC, Red Hat’s Pacheco said.
The leap second will kick in at 9 a.m. Wednesday in
Japan, just as businesses start work. Dominant mobile carrier NTT DoCoMo has
programmed its servers to slightly extend the length of each second over a couple
of hours before 9 a.m. to stay in sync with UTC, a spokeswoman said. Rival
SoftBank and major messaging app Line said they are also taking
countermeasures.
“We may see some small incidents with in-house computer
systems or ones that are very old and not well maintained,” said Tetsutaro
Uehara, a computer science professor at Ritsumeikan University in Kyoto. “But
they won’t cause big problems like we saw in 2012.”
With the concern it has caused among IT companies as well
as stock market regulators, the leap second has earned its share of detractors.
Representatives of various countries will continue to debate whether it should
be abolished at a November meeting of the International Telecommunication Union
(ITU) World Radiocommunication Conference. One alternative is a continuous time
scale without leap seconds that could be based on UTC.
“The suppression of the leap second would facilitate a
continuous time scale that would support all modern electronic navigation and
computerized systems and eliminate the need for specialized ad hoc time
systems,” an ITU spokesman said via email.
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