That's my speculation at the moment... that perhaps we need to jerk it back quickly before the applications start to get them closer together sooner rather than later. The app team is still researching how often they see this and if they can find a pattern. There are a couple of dozen servers involved and high volumes so that's not easy.
-----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Mark Post Sent: Monday, July 25, 2016 4:39 PM To: [email protected] Subject: Re: [LINUX-390] Back to the future? >>> On 7/25/2016 at 06:46 PM, Marcy Cortes <[email protected]> >>> wrote: > Answering my own post. > The latter HWCLOCK option is not for s390x (the code in > /etc/init.d/ntp ignores it if set if s390* ) > > But the former might be a good thing. > On the handful of test servers I ran it on, it gave me a smaller > offset as queried with Christian's ntpdate command (10ths of > milliseconds as opposed to > 1-3 milliseconds). I wouldn't think that would have a big impact on what NTP does. Earlier in that file, you should see this: NTPD_OPTIONS="-g -u ntp:ntp" The "-g" option says that the initial adjustment made to the system clock can be arbitrarily large (and will be done even if the clock is off by more than 1000 seconds). The option you're turning on simply allows the startup script to call sntp with the -S option, which means that stepping (as opposed to slewing) the clock on initial setting of the time. So, I guess if your system clock starts out _ahead_ of the "real time" then ntpd -g will take some time to bring it back, while NTPD_FORCE_SYNC_ON_STARTUP will allow it to be jerked backwards more quickly. Mark Post ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
