timothyhung
asked on
Can UEFI clock / system time changed by VMware?
I have a IBM X Server with UEFI setup and on the top of this, I have a VMware v5.1. I find that it is a strange combination between the UEFI Date / Time and the system date / time on VM. If I set the UEFI as local time and the time zone in VM. The time shown in VM is wrong after reboot, i.e. with the difference of the time zone.
What the setting should be? What is the mechanism to update the system time from UEFI to VM OS? Or vis versa, from VM OS to UEFI, if possible?
What the setting should be? What is the mechanism to update the system time from UEFI to VM OS? Or vis versa, from VM OS to UEFI, if possible?
Netman66
The VMs get time from the Host ESX OS (when the vmware tools are installed in the vm). Check the tz in the ESX settings.
ASKER
I mean VM time being the ESX server's date/time. Also, the guest OS on the top VM aligns the date/time of the ESX server. So, I believe there are some connection between the UEFI and the ESX (VM) on the system time.
ASKER
Does anyone has a suggestion? Please help.
Look in VMware Tools on the guest machine and under Time Sync, enable the time sync setting. That should help.
ASKER
John,
Thanks for your response. I know I can sync my server with NTP on VM. However, I want to know the affect on UEFI / BIOS and VM (system time and time zone).
Is it possible/ doable to update the UEFI time by OS, such as VM?
Thanks for your response. I know I can sync my server with NTP on VM. However, I want to know the affect on UEFI / BIOS and VM (system time and time zone).
Is it possible/ doable to update the UEFI time by OS, such as VM?
Is it possible/ doable to update the UEFI time by OS, such as VM?
A VM (Guest) time in the BIOS of the machine which is the VMware BIOS. I think you can only sync it as I described above or as you suggest by syncing with NTP.
I do not know of any other way.
A VM (Guest) time in the BIOS of the machine which is the VMware BIOS. I think you can only sync it as I described above or as you suggest by syncing with NTP.
I do not know of any other way.
ASKER
Folks,
I know my question maybe a bit tedious. But I do need some idea to verify some points.
I know my question maybe a bit tedious. But I do need some idea to verify some points.
ASKER
John,
Agree with you.
I can understand that UEFI updates VM and then VM updates the guest OS on system time, i.e. UEFI --> VM --> Windows, or VM or guest OS can direct update the system time with NTP. This is the basic rule for hardware design, control is built from bottom to top or upward to next level. However, someone tries to convince me that VM may change the system time from VM back to UEFI in one incident. I have doubt with this. I need more evident to find out the fact.
Agree with you.
I can understand that UEFI updates VM and then VM updates the guest OS on system time, i.e. UEFI --> VM --> Windows, or VM or guest OS can direct update the system time with NTP. This is the basic rule for hardware design, control is built from bottom to top or upward to next level. However, someone tries to convince me that VM may change the system time from VM back to UEFI in one incident. I have doubt with this. I need more evident to find out the fact.
I am not even sure where UEFI comes into time. UEFI = Unified Extensible Firmware Interface and is a replacement for BIOS.
I do not think VMware BIOS is UEFI. And then in any event, time is a setting in any BIOS. The Guest time can be independent and set via an Internet Clock, or it can be sync'd by VMware tools Time Sync. That is about all there is.
someone tries to convince me that VM may change the system time from VM back to UEFI in one incident.
I don't think that is possible. I do not know if it is even relevant. Time has nothing to do with UEFI so far as I know.
I do not think VMware BIOS is UEFI. And then in any event, time is a setting in any BIOS. The Guest time can be independent and set via an Internet Clock, or it can be sync'd by VMware tools Time Sync. That is about all there is.
someone tries to convince me that VM may change the system time from VM back to UEFI in one incident.
I don't think that is possible. I do not know if it is even relevant. Time has nothing to do with UEFI so far as I know.
ASKER
I do not mean VMware BIOS is UEFI. I know they are different, one software and one more on hardware. In my case, the time set in UEFI/BIOS is independent from my VM.
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ASKER
John,
Thanks for your input. It is exactly what I understand. In fact, I need an independence to comment on the VM and UEFI as, I mentioned, someone (from big blue) said that the UEFI time may be changed by VM and caused a problem. Although we have resolve the problem at once, I still want to understand more and prevent similar situation in future.
I would accept your comment as a solution. However, there is any further comment from the floor. I would like to have for reference.
Thanks again for everyone.
Thanks for your input. It is exactly what I understand. In fact, I need an independence to comment on the VM and UEFI as, I mentioned, someone (from big blue) said that the UEFI time may be changed by VM and caused a problem. Although we have resolve the problem at once, I still want to understand more and prevent similar situation in future.
I would accept your comment as a solution. However, there is any further comment from the floor. I would like to have for reference.
Thanks again for everyone.
@timothyhung - Thank you and I was happy to help you with this.