`Ntpd` imposta il clock hardware?

Fa ntpdset orologio hardware?

Ha ntpdorologio set hardware se mi passate -ql'opzione (correzione media di una volta)?

Linux 3.5.6, ntp 4.2.6.p5.

Qui è scritto che ntpd sincronizza l'orologio di sistema con l'hardware ogni 11 minuti, ma non riesco a trovare un riferimento a questo nel mans ntpd.

Una domanda simile è stata posta su Serverfault.com . Questa era la risposta

Dalla hwclockpagina man su RHEL 4.6:

This mode (we'll call it "11 minute mode") is off until something turns it on.  The ntp
daemon  xntpd  is  one thing  that  turns  it on.  You can turn it off by running
anything, including hwclock --hctosys, that sets the System Time the old fashioned way.

To see if it is on or off, use the command adjtimex --print and look at the value of
"status".  If the "64" bit of this number (expressed in binary) equal to 0, 11 minute mode 
is on.  Otherwise, it is off.

Quindi, in virtù della tua corsa hwclock --set, probabilmente l'hai disattivato. Allo stesso modo è possibile verificare l'output di adjtimex --printper confermare.

Guarda tu stesso (il seguente script mostra lo "stato temporale" corrente quasi in tempo reale, registrando improvvise variazioni di valore)

#!/bin/sh
set -eu

get_time() {
    local line="$1"
    timedatectl \
        | sed -nE $line'p' \
        | sed -E 's/.* ([0-9]+):([0-9]+):([0-9]+).*/\1\2\3/'
}


get_time_status() {
    adjtimex --print \
        | grep -F status \
        | awk '{print "obase=2;" $2}' \
        | bc
}


num_diff() {
    local a="$1" b="$2"
    echo "ah = ${a:0:2}; am = ${a:2:2}; as = ${a:4:2}
        bh = ${b:0:2}; bm = ${b:2:2}; bs = ${b:4:2}
        a = ah * 60 * 60 + am * 60 + as
        b = bh * 60 * 60 + bm * 60 + bs
        if (a > b) a - b else b - a" | bc
}


print_line() {
    local f1="$1" f2="$2"
    printf "%20s %-$(($(tput cols) - 21))s\n" "$f1" "$f2"
}


localt=
universalt=
rtct=
ntp_enabled=
ntp_synchronized=
time_status=

localt_prv="$(get_time 1)"
universalt_prv="$(get_time 2)"
rtct_prv="$(get_time 3)"
ntp_enabled_prv="$(timedatectl | grep -E 'NTP enabled' | awk '{print $3}')"
ntp_synchronized_prv="$(timedatectl | grep -E 'NTP synchronized' | awk '{print $3}')"
time_status_prv="$(get_time_status)"

while true; do
    localt="$(get_time 1)"
    universalt="$(get_time 2)"
    rtct="$(get_time 3)"
    ntp_enabled="$(timedatectl | grep -E 'NTP enabled' | awk '{print $3}')"
    ntp_synchronized="$(timedatectl | grep -E 'NTP synchronized' | awk '{print $3}')"
    time_status="$(get_time_status)"

    if [ "$(num_diff $localt $localt_prv)" -gt 5 ]; then
        print_line "[$(date +%H:%M:%S)]" "localt: $localt_prv -> $localt"
    fi
    if [ "$(num_diff $universalt $universalt_prv)" -gt 5 ]; then
        print_line "[$(date +%H:%M:%S)]" "universalt: $universalt_prv -> $universalt"
    fi
    if [ "$(num_diff $rtct $rtct_prv)" -gt 5 ]; then
        print_line "[$(date +%H:%M:%S)]" "rtct: $rtct_prv -> $rtct"
    fi
    if [ "$ntp_enabled" != "$ntp_enabled_prv" ]; then
        print_line "[$(date +%H:%M:%S)]" "ntp_enabled: $ntp_enabled_prv -> $ntp_enabled"
    fi
    if [ "$ntp_synchronized" != "$ntp_synchronized_prv" ]; then
        print_line "[$(date +%H:%M:%S)]" "ntp_synchronized: $ntp_synchronized_prv -> $ntp_synchronized"
    fi
    if [ "$time_status" != "$time_status_prv" ]; then
        print_line "[$(date +%H:%M:%S)]" "time_status: $time_status_prv -> $time_status"
    fi

    print_line local: "$localt"
    print_line universal: "$universalt"
    print_line rtc: "$rtct"
    print_line 'NTP enabled:' "$ntp_enabled"
    print_line 'NTP synchronized:' "$ntp_synchronized"
    print_line 'time status:' "$time_status"

    sleep 1

    localt_prv="$localt"
    universalt_prv="$universalt"
    rtct_prv="$rtct"
    ntp_enabled_prv="$ntp_enabled"
    ntp_synchronized_prv="$ntp_synchronized"
    time_status_prv="$time_status"

    printf '\033[6A'
done