On 18 Jan 2016 09:22, "Claudio Scordino" <claudio at evidence.eu.com> wrote: > > I need to create a reliable and accurate synchronization between two CentOS 6 machines connected through a direct Ethernet connection. > > I've seen that on Linux several implementation of the IEEE 1588 Precision Time Protocol (PTP) exist: > > PTPd: > Apparently, this is the original implentation > Apparently, it is still maintained > PTPd2: > A new version meant to supersede the previous implementation > Apparently unmaintained > For CentOS 6, available only in the EPEL repositories > PTPv2d: > A further implementation > Unmaintained as well > linuxptp: > A specific implementation for Linux > Maintained > Available on the CentOS repositories > Suggested by the RedHat documentation for both RedHat 6 and RedHat 7 > > My questions follow: > > Why does the RedHat documentation suggest the use of linuxptp for RedHat 6 (based on Linux kernel 2.6) despite the linuxptp documentation says that a Linux kernel version 3.0 or newer is needed ? Because Red Hat backport many drivers and features so the 2.6.32 (not just 2.6) version number is totally irrelevant as to the actual features available in the kernel. > Which are differences between PTPd2 and Linuxptp in terms of reliability and timing accuracy ? No idea but there's probably a good reason RH picked up linuxptp as the formally supported version and the other is only in EPEL and not supported by them. > Which one should I prefer on CentOS 6 and on CentOS 7, respectively ? Keep in the same for both to ease your maintenance burden in your configuration management. > Why either PTPd2 and Linuxptp do not synchronize immediately and often need me to start/stop the service several times or manually change system time through date to make the machine synchronize ? > Sorry don't use it here so don't have a test bed... If there is a verbose or debug arguments check those for more detailed logs. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.centos.org/pipermail/centos-devel/attachments/20160119/867683c4/attachment-0008.html>