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swo0sh_gt_13163
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Apr 22, 2015

NTP time difference between Active / Standby appliance

Hello Folks,

It has been quite sometime when I post a question on DevCentral. So here we go, I have 2 F5 A/S appliances. Both are pointing to 2 NTP servers as 10.13.1.11 and 10.13.1.12. NTP traffic is passing through other than Management Interface so far.

What has been observed is, Active appliance is showing correct time as per the NTP server, however the standby appliance is showing 3 minutes of difference compare to the Active appliance. Even you sync the time manually, it slowly experience delay, and time difference start getting increased between both of the appliances.

Following is the result of the NTPQ -PN from Active and standby.

[root@Company_F5-3900U1:Active:In Sync] config  ntpq -np
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 10.13.1.12      10.13.1.11       2 u   19   64  377    2.077  -43725.  11.051
 10.13.1.11      .LOCL.           1 u   59   64


[root@Company_F5-3900U2:Standby:In Sync] config  ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 10.13.1.12      10.13.1.11       2 u   18   64  377    1.947  -222609  33.485
 10.13.1.11      .LOCL.           1 u   21   64  377    1.953  -222588  28.426

If you see the Offset value on Standby appliance, that justifies the fact why there is a time difference between Active and Standby unit. The NTP servers are reachable via a DMZ interface i.e. 1.1. Both of the appliances have same configured of interfaces along with the media settings.

Following is the interface property of both of the appliances, which is exactly same.

   root@(Company_F5-3900U2)(cfg-sync In Sync)(Standby)(/Common)(tmos) list net interface 1.1
net interface 1.1 {
    if-index 80
    mac-address 00:01:d7:e6:6d:44
    media-active 1000T-FD
    media-max 1000T-FD
    mtu 1800
}

Any help?

Darshan

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