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Why did the leap second cause trouble with AS Java?

Former Member
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Last weekend another leap second was introduced and propagated via NTP. Suprisingly this caused problems with high system CPU time on Linux systems with AS Java. SLES 11 and RHEL6 were affected, probably others also.

Is there any SAP note about this issue? I think we have some years time until the next leap second approaches, hopefully the AS Java instances will be immune by then.

(Note: This problem is not related to the Linux system hang problem due to leap seconds, SuSE and Red Hat already had included bugfixes against that.)

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
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Dear Mark

SAP has identified this problem and has released an SAP Note 1738172. Please go through it.

Thanks

Tapan

Answers (2)

Answers (2)

Former Member
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Hello Mark

"Leap Second" issue can be resolved by restarting NTPD service on LINUX OS. You may check below links:

http://www.wired.com/wiredenterprise/2012/07/leap-second-bug-wreaks-
havoc-with-java-linux/

http://pedroalves-bi.blogspot.in/2012/07/java-leap-second-bug-how-to-
fix-your.html

There is no sap note available on leap-second bug.

Thanks

Tapan

Former Member
0 Kudos

Hi Mark,

I fear this problem is connected to JEE stack just partly, but very often to the operating system below. With "just high CPU usage" you were lucky, as other administrators report complete server crashes with Linux and hardware from different vendors.

Problem seems to get worse the more load is on the host, but this may be connected to special environments. Also the problem has been reported for other JAVA based environments too (JBOSS, ..).

Some vendors provide updates to fix this, others recommend a reboot - and sometimes it is just advised to just shutdown ntpd, run ntpdate and start ntpd again.

FYI CPU load:

https://lkml.org/lkml/2012/6/30/122

FYI time smear:

http://googleblog.blogspot.de/2011/09/time-technology-and-leaping-seconds.html#!/2011/09/time-techno...

Regards,

Peter