On Mon, 2011-07-18 at 12:22 +0200, Per Jessen wrote:
Roger Oberholtzer wrote:
On Mon, 2011-07-18 at 11:11 +0200, Per Jessen wrote:
That is understood, but I thought you had an issue with the GPS PPS signal being unavailable and the local clock not being sufficiently accurate.
Exactly. Sometimes the systems are powered on when the vehicle is in, say, a garage. Or under trees. The GPS may or may not provide the PPS signal before it sees satellites. It is not deterministic. At least using rules the operators can also follow reliably. This points out another requirement: we need to be able to indicate to the operator when the system thinks it has an accurate time.
ntp will tell you that - it is one of the status indicators in the ntpq display. Or you could monitor the logfile and check for stratum changes. (stratum 0 = GPS, anything else = unsynced). There might even be an SNMP trap for this, you never know.
Here is an example:
# ntpq -pn remote refid st t when poll reach delay offset jitter ============================================================================== *127.127.8.1 .DCFa. 0 l 57 64 177 0.000 -8.956 2.714 127.127.1.0 .LOCL. 10 l 59 64 377 0.000 0.000 0.008 +162.23.41.34 .HBGi. 1 u 58 64 377 55.101 -5.126 120.944 +129.132.2.21 129.132.2.22 2 u 48 64 377 38.736 -12.524 99.586 192.168.7.255 .BCST. 16 u - 16 0 0.000 0.000 0.008 212.25.14.63 .BCST. 16 u - 16 0 0.000 0.000 0.008
This says that this time server is synced to DCF (the asterisk indicator), and that two good external time sources are available (stratum 1 and 2). There is also an indicator for a PPS signal, but I don't use one.
This looks promising. I guess I will need to make a log file parser if SNMP is not available. Thanks for this pointer. Of course, I need to sort out the ntp issues I have before this is an issue.
-- Per Jessen, Zürich (17.9°C)
Yours sincerely, Roger Oberholtzer OPQ Systems / Ramböll RST Office: Int +46 10-615 60 20 Mobile: Int +46 70-815 1696 roger.oberholtzer@ramboll.se ________________________________________ Ramböll Sverige AB Krukmakargatan 21 P.O. Box 17009 SE-104 62 Stockholm, Sweden www.rambollrst.se -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org