System Date and Time, iDRAC Timezone and sync

  • 29 September 2016
  • 2 replies
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Hi,

I'm deploying a Nutanix cluster with three Dell nodes. The question rose about what timezone should be selected in the iDRAC.

It was at first hard for me to undertsand how was the time set into the DRAC and the Bios, and I finally go this:

Set Both NTP and Time zone
In this method user will configure NTP and Time zone. In this case iDRAC will sync the time with NTP server and selected Time zone will be also applied. iDRAC will sync NTP server’s UTC/GMT time, so it is important that you configure correct time zone while configuring NTP on iDRAC. You can configure up to three NTP servers. It is always recommended to configure all three NTP servers for accuracy. We support IPv4, IPv6 and FQDN format for configuring NTP server address When NTP mode is enabled and iDRAC has received time through this interface, iDRAC will ignore any attempts to set iDRAC time through the server (BIOS, Open Manage, etc.) or CMC (for blade servers).

Therefore, what I understand is that once the Timezone is set to local (i.e. Europe/Zurich) and NTP is enabled and properly configured, the system clock will be sync with the time provided from the DRAC, hence, from the time servers.

Does this has any impact on Nutanix ? I couldn't fine any best practice on this matter.

2 replies

Userlevel 7
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This does not impact us, so we dont have an opinion one way or the other, I'd defer to dell's default recommendations
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Hi Gandahar,

Having experienced this recently I can shed some light.

The BIOS time is critical and must be set to the correct time. As BIOS do not contain timezones UTC0 time must be used.

This will ensure the hypervisors have the correct time when the cluster is created (assuming AHV). The default timezone is PDT. I have found that when applying AHV patches the timezone is always reverted to PDT, even if you have specified another custom timezone (this may have been resolved?)

The iDRAC timezone is inconsequential. This timezone is used to ensure the logs are timestamped to a timezone that is meaningful to you.

AHV will retrieve NTP updates from the ntp server you specify during cluster creation.

Its important to ensure that the foundation VM (if using this), has the correct time. If using AHV the foundation VM will push its time to the CVM. Timezones again are inconsequntial as long as the time on the device is the correct time for the timezone choosen on the foundaiton VM.

Its important that CVM and AHV times do not become out of sync (CVM forward of AHV), otherwise time will drift too far and never sync again (until a cluster stop/start). By then it will be too late and this will result in your cluster unable to start due to cassandra timestamps rolling back.

Changing timezone in Prism is OK and will affect CVM only. This will make logs easier to read.

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