[ntp:questions] Re: Clock skew too great

Sabrina Lautier slautier at amadeus.com
Tue Nov 15 10:47:14 UTC 2005


First of all thanks a lot for your help.
Sorry for the late delay but I was off yesterday.

> How large is the clock skew?
Huge... to give you an idea last Thursday around 5pm I synchronized the
date and time and today at 11:30am the time on the machine is 14:23.

> What is your kernel parameter "HZ" set to ?
To nothing, the variable is not set.

Would there be a link with the processor clock frequency ?

$ dmesg | grep -i hz
time.c: Using 1.193182 MHz PIT timer.
time.c: Detected 2405.495 MHz processor.
Detected 12.528 MHz APIC timer.
ide: Assuming 33MHz system bus speed for PIO modes; override with idebus=xx
powernow-k8:    0 : fid 0x10 (2400 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0xe (2200 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xc (2000 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xa (1800 MHz), vid 0xc (1250 mV)
powernow-k8:    0 : fid 0x10 (2400 MHz), vid 0x6 (1400 mV)
powernow-k8:    1 : fid 0xe (2200 MHz), vid 0x8 (1350 mV)
powernow-k8:    2 : fid 0xc (2000 MHz), vid 0xa (1300 mV)
powernow-k8:    3 : fid 0xa (1800 MHz), vid 0xc (1250 mV)

> If it's set to 1000, try changing it to 100.
Should I set it to 100 ?
In which file to you set it ?

What surprises me is that ntp does not report any error (file /var/log/ntp
is empty).

Rgds,
Sabrina


                                                                           
                                                                           
                                                                           
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    "Richard B. Gilbert"                                           Subject 
    <rgilbert88 at comcast.net>          [ntp:questions] Re: Clock skew too   
                                      great                                
                                                                           
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    11/11/2005 22:16                                                       
                                                                           




Sabrina Lautier wrote:

>All,
>
>I've got time skew errors on all HP DL385 servers with 2 network cards
>configured.
>This issue only occurs on this specific hardware - it does not on our HP
>DL145.
>And yet the Linux distribution is the same (SuSe SLES9 AMD64) and so is
the
>ntp package and configuration.
>On a HP DL385 if only 1 network card is configured this issue does not
>exist.
>
># On an HP DL385
>$ uname -a
>Linux dl385_linux 2.6.5-7.151-smp #1 SMP Fri Mar 18 11:31:21 UTC 2005
>x86_64 x86_64 x86_64 GNU/Linux
>
># On an HP DL145
>$ uname -a
>Linux dl145_linux 2.6.5-7.151-smp #1 SMP Thu Jun 2 12:07:05 UTC 2005
>x86_64 x86_64 x86_64 GNU/Linux
>
># On both hardware
>$ rpm -q xntp
>xntp-4.2.0a-23.4
>
>$ cat /etc/ntp.conf
>
>##
>## Outside source of synchronized time
>##
>## server xx.xx.xx.xx           # IP address of server
>
>##
>## Miscellaneous stuff
>##
>
>driftfile /var/lib/ntp/drift/ntp.drift # path for drift file
>
>logfile /var/log/ntp            # alternate log file
>server ntp1.nce.amadeus.net
>server ntp2.nce.amadeus.net
>server ntp3.nce.amadeus.net
># logconfig =syncstatus + sysevents
># logconfig =all
>
># statsdir /tmp/                # directory for statistics files
># filegen peerstats  file peerstats  type day enable
># filegen loopstats  file loopstats  type day enable
># filegen clockstats file clockstats type day enable
>
>#
># Authentication stuff
>#
># keys /etc/ntp.keys            # path for keys file
># trustedkey 1 2 3 4 5 6 14 15  # define trusted keys
># requestkey 15                 # key (7) for accessing server variables
># controlkey 15                 # key (6) for accessing server variables
>
>The network cards are not the same:
>DL385: Compaq NC7782 Gigabit Server Adapter
>DL145: AMD NetXtreme BCM5704 Gigabit Ethernet
>
>This issue if very annoying as services like winbind and cvs does not work
>properly:
>
>$ grep skew /var/log/messages
>Nov  9 18:58:32 dl385_linux winbindd[2895]:   Kinit failed: Clock skew too
>great
>
>The only current work-around I found is to restart xntpd every minute in
>the crontab.
>
>Could you please help ?
>
>Thx a lot for your help.
>
>Rgds,
>Sabrina
>
>_______________________________________________
>questions mailing list
>questions at lists.ntp.isc.org
>https://lists.ntp.isc.org/mailman/listinfo/questions
>
>
>
How large is the clock skew?  What is your kernel parameter "HZ" set
to?  If it's set to 1000, try changing it to 100.

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