Domain Computers: Clock Sync

gjacobse

I'm getting a few reports from one of our clients that they desktop are showing incorrect clock times even though they are set by the Primary DC.

the DC is set to pull time from a known good NTP server.

Even after rebooting, the clocks are incorrect.

Any thoughts as to why this could be?

JaredBusch

You never stated if the DC was actually correct.

gjacobse

When I checked it the other day - it was, but oddly - today it is 6 minutes fast.

re-setting all the NTP servers

travisdh1

It's the default client sync still only once per week? I'd they're all different but close, it could be the local clocks going bad (bios batteries starting to go possibly).

StorageNinja

@gjacobse Is it Virtual? If so what hypervisor? (Different best practices)

gjacobse

@storageninja said in Domain Computers: Clock Sync:

@gjacobse Is it Virtual? If so what hypervisor? (Different best practices)

Good point - I can sync the VM all day long, but the the HyperVisor is off,.. nothing will change.

Updated the HV, and now the VM seem correct.

stacksofplates

@gjacobse said in Domain Computers: Clock Sync:

@storageninja said in Domain Computers: Clock Sync:

@gjacobse Is it Virtual? If so what hypervisor? (Different best practices)

Good point - I can sync the VM all day long, but the the HyperVisor is off,.. nothing will change.

Updated the HV, and now the VM seem correct.

I'm sorry, what does this mean?

Especially this statement "but the the HyperVisor is off,.. nothing will change". Not being a jerk, I honestly couldn't follow it.

gjacobse

DC4 is a virtual machine. changes to it are likely over rode by the Hypervisor or physical hardware that were wrong.

By updating the physical hardware, and then running w32tm /resync the time updated.

Kelly

@stacksofplates said in Domain Computers: Clock Sync:

@gjacobse said in Domain Computers: Clock Sync:

@storageninja said in Domain Computers: Clock Sync:

@gjacobse Is it Virtual? If so what hypervisor? (Different best practices)

Good point - I can sync the VM all day long, but the the HyperVisor is off,.. nothing will change.

Updated the HV, and now the VM seem correct.

I'm sorry, what does this mean?

Especially this statement "but the the HyperVisor is off,.. nothing will change". Not being a jerk, I honestly couldn't follow it.

At least Hyper-V has the clients pull time from the host by default. It doesn't matter what the settings are in the OS, it is a hypervisor setting that has to be turned off before your w32tm settings will do a thing.

StorageNinja

@kelly said in Domain Computers: Clock Sync:

At least Hyper-V has the clients pull time from the host by default. It doesn't matter what the settings are in the OS, it is a hypervisor setting that has to be turned off before your w32tm settings will do a thing.

VMware VMtools will also pull time from the host. From this, you should..

Check the Host BIOS Time (UTC)
Set the Host BIOS to draw from NTP (iDRAC/iLO)
Set ESXi (If also used) to use NTP also (Service off by default).

Note there are a lot of free NTP clocks to poll from.
time.windows.com is generally up.

If you are running ESXi there is a built-in health check (under vSAN health Checks) that will alert you to time drift between any hosts and the vCenter to identify this.

dbeato

@gjacobse said in Domain Computers: Clock Sync:

DC4 is a virtual machine. changes to it are likely over rode by the Hypervisor or physical hardware that were wrong.

By updating the physical hardware, and then running w32tm /resync the time updated.

The issue will resurface again as the BIOS is losing time and will be pulled again wrongly on the host. Have you tried not syncing the time of the VM through the Hypervisor and turning of Time Synchronization for this DC?