<p dir="ltr"><br>
On 18 Jan 2016 09:22, "Claudio Scordino" <<a href="mailto:claudio@evidence.eu.com">claudio@evidence.eu.com</a>> wrote:<br>
><br>
> I need to create a reliable and accurate synchronization between two CentOS 6 machines connected through a direct Ethernet connection.<br>
><br>
> I've seen that on Linux several implementation of the IEEE 1588 Precision Time Protocol (PTP) exist:<br>
><br>
> PTPd:<br>
> Apparently, this is the original implentation<br>
> Apparently, it is still maintained<br>
> PTPd2:<br>
> A new version meant to supersede the previous implementation<br>
> Apparently unmaintained<br>
> For CentOS 6, available only in the EPEL repositories<br>
> PTPv2d:<br>
> A further implementation<br>
> Unmaintained as well<br>
> linuxptp:<br>
> A specific implementation for Linux<br>
> Maintained<br>
> Available on the CentOS repositories<br>
> Suggested by the RedHat documentation for both RedHat 6 and RedHat 7<br>
><br>
> My questions follow:<br>
><br>
> 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 ?</p>
<p dir="ltr">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.</p>
<p dir="ltr">> Which are differences between PTPd2 and Linuxptp in terms of reliability and timing accuracy ?</p>
<p dir="ltr">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.</p>
<p dir="ltr">> Which one should I prefer on CentOS 6 and on CentOS 7, respectively ?</p>
<p dir="ltr">Keep in the same for both to ease your maintenance burden in your configuration management.</p>
<p dir="ltr">> 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 ?<br>
></p>
<p dir="ltr">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.<br></p>