- using NTP hosts that exist on local network
- disabling time sync in the VM host
Note: If internal NTP hosts are not an option, external NTP hosts/pools can be used, but not recommended for long term solutions.
Disable time syncronization in VM host
Symantec, Microsoft, and VMWare recommend time sync to be disabled in the VM host, and the guest OS/server (SMG in this case) control the system clock.
For VMWare, see the "VMware Tools Time Synchronization and Configuration" section of Timekeeping best practices for Windows, including NTP (1318) by VMWare.
For Hyper-V (per https://superuser.com/questions/1214966/disabling-time-synchronization-with-hyper-v):
- Shut down virtual machine.
- Open Hyper-V Manager.
- Right click on the VM in question, and select "Integration Services".
- Uncheck "Time Syncronization".
- Click Apply.
- Restart VM.
Configure NTP in SMG
- Go to Administration > Hosts > Config > server > DNS/Time tab.
- Click on "Use NTP servers" radio button.
- Enter NTP hosts to be used. Priority diminishes down the list.
- If all SMG hosts will use the same DNS and NTP servers, check "Apply above settings to all servers".
- Click Save.
- If step 4 is not performed, repeat for each SMG host.