Linux Time Configuration

• Hardware Clock (UTC) sets system clock contain the time zone variable) in booting up.  NTP server give time to system clock. "Date" Set system clock, "hwclock" Set hardware clock

• hwclock--SYSTOHC //sync The system time to hardware time

• hwclock--hctosys //sync The hardware time to system time
• Timedatectl /To set timezone, Enable/disanble NTP
• Stratum (can be checked by NTPQ)//In the world of NTP, stratum levels define the distance from the reference clock. The basic definition of a stratum-1 time server is so it was directly linked (not over a network path) to a reliable sour Ce of UTC time such as GPS, WWV, or CDMA transmissions. A stratum-1 time server acts as a primary network time standard.  A stratum-2 Server is connected to the STRATUM-1 server over A NETWORK PATH. Thus, a stratum-2 server gets its time via NTP packet requests from a STRATUM-1 server A reference clock is a stratum-0 de  Vice that are assumed to be accurate and have lttle or no delay associated with it. Https://www.endruntechnologies.com/stratum1.htm
• /etc/ntp.conf for NTP config
• chrony //Another Sync protocol (more Accuruate than NTP), configure file Avaibale at  chrony.conf,

  chronyc sources     //Verify the sync  server  
  Sources = 4
  MS name/ip address stratum Poll Reach Lastrx last sample
  ======================= ========================================================
  ^-time.rdg.uk.as44574.net 2 8 123 +56ms[+56ms] +/- 60ms
  ^-time.videxio.net 2 8 123 +59ms[+59MS] +/-67ms
  ^* 85.199.214.100 1 8 124-6891us[ -56ms] +/-72ms
  ^-nero.grnet.gr 1 8 267 108 +55ms[+55MS] +/-38ms

  
  

[Email protected]:/etc/chrony# chronyc tracking
Reference id:85.199.214.100 (85.199.214.100)
Stratum:2
Ref Time (UTC): Wed APR 25 07:48:37 2018
System time:0.001474089 seconds slow of NTP time
Last offset: -0.048626836 seconds
RMS offset:0.015923370 seconds
frequency:78.733 ppm Fast
Residual freq: -166.953 ppm
skew:1000000.000 ppm
Root delay:0.144223 seconds
Root dispersion:221.504059 seconds
Update interval:257.2 seconds
Leap Status:normal

Linux Time Configuration