[2024-feb-29] Sad news: Eric Layton aka Nocturnal Slacker aka vtel57 passed away on Feb 26th, shortly after hospitalization. He was one of our Wiki's most prominent admins. He will be missed.
Differences
This shows you the differences between two versions of the page.
Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision | ||
howtos:network_services:ntp [2013/03/01 13:49 (UTC)] – Added an introduction + some explanations + edited some sections kikinovak | howtos:network_services:ntp [2014/02/17 06:30 (UTC)] – kikinovak | ||
---|---|---|---|
Line 9: | Line 9: | ||
===== Introduction ===== | ===== Introduction ===== | ||
- | When several users manipulate shared data on different client PCs on a network, it's important that these machines are all synchronized. Unfortunately, | + | When several users manipulate shared data on different client PCs on a network, it's important that these machines are all synchronized. This is especially true if you share files over NFS, or if you use NIS for centralized authentication. You'll get all sorts of weird errors if your clocks are out of sync. Unfortunately, |
That's where NTP (//Network Time Protocol//) comes in handy. It allows networked machines to adjust their clocks so as to be perfectly synchronized. A series of public time servers on the Internet allow the reception of the exact time. From this point, we can use NTP in several ways. | That's where NTP (//Network Time Protocol//) comes in handy. It allows networked machines to adjust their clocks so as to be perfectly synchronized. A series of public time servers on the Internet allow the reception of the exact time. From this point, we can use NTP in several ways. | ||
Line 172: | Line 172: | ||
. | . | ||
ntpd -qg & | ntpd -qg & | ||
+ | | ||
+ | ===== Monitor the performance of ntpd ===== | ||
+ | |||
+ | You will notice that the logfile ''/ | ||
+ | |||
+ | < | ||
+ | statsdir / | ||
+ | statistics loopstats | ||
+ | filegen loopstats file loops type day link enable | ||
+ | </ | ||
+ | |||
+ | You have to create the statsdir manually. Once the configuration changes are in effect, '' | ||
+ | < | ||
+ | 56690 3950.569 0.001199636 2.297 0.001830770 0.571576 10 | ||
+ | </ | ||
+ | |||
+ | The first and second number are the UTC time (expressed as [[http:// | ||
+ | |||
+ | To monitor the performance of '' | ||
+ | |||
+ | < | ||
+ | $ awk ' | ||
+ | $ awk ' | ||
+ | $ gnuplot | ||
+ | gnuplot> set xzeroaxis | ||
+ | gnuplot> plot ' | ||
+ | gnuplot> plot ' | ||
+ | </ | ||
+ | |||
+ | Given enough data, visual examination of the plots will allow you to see peculiarities in '' | ||
====== Sources ====== | ====== Sources ====== | ||
* Originally written by [[wiki: | * Originally written by [[wiki: | ||
+ | * Performance monitoring section contributed by Dominik Drobek | ||
<!-- Please do not modify anything below, except adding new tags.--> | <!-- Please do not modify anything below, except adding new tags.--> | ||
<!-- You must remove the tag-word " | <!-- You must remove the tag-word " | ||
{{tag> | {{tag> |