[Pool] time reset

Ask Bjørn Hansen ask at develooper.com
Fri Mar 25 07:18:36 UTC 2011


On Mar 24, 2011, at 21:13, Chuck Swiger wrote:

> On Mar 24, 2011, at 7:42 PM, Ryan Tucker wrote:
>> If you do run ntpd, everything is fine.  It has no problems keeping
>> accurate time, and the PLL stats show no differences from real hardware.
>> It makes for perfectly capable pool servers, too.
> 
> Please show me some data, ie, "ntpq -pcrv" output.....

RHEL5 with Xen (with a bunch of busy virtual machines; this is from one of the DomU's):

$ ntpq -pcrv -n
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+204.235.61.9    130.207.244.240  2 u    3  256  377   68.210    0.773   0.492
-149.20.68.17    204.123.2.72     2 u    5  256  377    9.867    2.227   0.276
+216.144.229.211 209.81.9.7       2 u   55  256  377    1.315    0.425   1.145
-207.171.7.151   164.67.62.212    2 u    2  256  377    0.177   -1.297   2.468
-207.171.7.152   164.67.62.212    2 u  255  256  377    0.281   -0.944   1.295
*64.142.122.38   .PPS.            1 u  195  256  377   20.514    0.845   0.910
assID=0 status=0664 leap_none, sync_ntp, 6 events, event_peer/strat_chg,
version="ntpd 4.2.2p1 at 1.1570-o Thu Nov 26 11:35:07 UTC 2009 (1)",
processor="i686", system="Linux/2.6.18-194.17.1.el5xen", leap=00,
stratum=2, precision=-20, rootdelay=20.514, rootdispersion=24.269,
peer=53430, refid=64.142.122.38,
reftime=d136bb52.54000de8  Thu, Mar 24 2011 23:57:22.328, poll=8,
clock=d136bf16.ef99279c  Fri, Mar 25 2011  0:13:26.935, state=4,
offset=0.896, frequency=-61.361, jitter=0.942, noise=0.553,
stability=0.418, tai=0


Compared to an ntpd running on "real hardware" (RHEL6) on the same network and with the same configuration:

$ ntpq -pcrv -n
assID=0 status=0664 leap_none, sync_ntp, 6 events, event_peer/strat_chg,
version="ntpd 4.2.4p8 at 1.1612-o Thu May 13 14:38:25 UTC 2010 (1)",
processor="x86_64", system="Linux/2.6.32-71.18.2.el6.x86_64", leap=00,
stratum=2, precision=-24, rootdelay=20.641, rootdispersion=16.029,
peer=9542, refid=64.142.122.38,
reftime=d136bea6.4abedf91  Fri, Mar 25 2011  0:11:34.291, poll=9,
clock=d136bf75.93abbfca  Fri, Mar 25 2011  0:15:01.576, state=4,
offset=-0.209, frequency=-15.105, jitter=0.151, noise=0.251,
stability=0.048, tai=0
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+204.235.61.9    130.207.244.240  2 u  412  512  377   67.985   -0.047   0.585
+69.50.219.51    128.138.188.172  2 u  386  512  377   11.790   -0.165   0.177
-209.114.111.1   132.163.4.101    2 u  406  512  377   50.861   -0.420   0.247
-207.171.7.151   164.67.62.212    2 u  407  512  377    0.408   -2.047   0.064
-207.171.7.152   164.67.62.212    2 u  397  512  377    0.213   -1.945   0.041
*64.142.122.38   .PPS.            1 u  207  512  377   20.641   -0.250   0.126



And just for completeness, a virtual machine on a KVM host (CentOS 5):

$ ntpq -pcrv -n
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
*207.171.7.151   164.67.62.212    2 u 1455  68m  377    1.873   -1.133   1.042
 10.50.0.15      207.171.7.151    3 u  450 1024  377    1.386   -4.070   1.243
+10.50.0.30      74.117.214.2     2 u  343 1024  377    1.352    0.002   0.080
-10.50.30.31     64.235.98.66     3 u  217 1024  377   80.159   -6.319   0.686
-10.50.30.32     207.171.7.152    3 u  393 1024  377   79.788   -2.996   0.342
-10.50.30.2      90.171.183.58    3 u  441 1024  377   79.321    6.976   0.380
+10.50.20.3      207.171.7.152    3 u 1430  68m  377   17.559   -0.795   0.386
assID=0 status=06f4 leap_none, sync_ntp, 15 events, event_peer/strat_chg,
version="ntpd 4.2.2p1 at 1.1570-o Sat Dec 19 00:56:13 UTC 2009 (1)",
processor="x86_64", system="Linux/2.6.18-194.17.4.el5", leap=00,
stratum=3, precision=-20, rootdelay=3.475, rootdispersion=78.137,
peer=24284, refid=207.171.7.151,
reftime=d136ba3a.698682bc  Thu, Mar 24 2011 23:52:42.412, poll=12,
clock=d136bfe9.3b3c2366  Fri, Mar 25 2011  0:16:57.231, state=4,
offset=-0.849, frequency=0.209, jitter=1.166, noise=1.214,
stability=0.041, tai=0



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