No save option in Dell R710 BIOS

In Dell you hit ESC to exit BIOS.  Then you will see 3 options.  Save changes and exit, DIscard, or Return to Setup.  
You hit Save - 1st option.  System will boot and changes saved.

True but it is Windows that manages time.  BIOS has a clock but settings are managed by Windows not in BIOS (certainly not my BIOS).

The OS is irrelevant here.  System's BIOS is in questions.

I have not seen any BIOS that will change time. The operating system does that.

So to be more exact, I change my time in the OS for daylight saving time and that new time is save in a BIOS area. When I restart the new time is still there.

You can do it other way around.  Change time in BIOS and it will change the OS time.  
The true time of the computer is the BIOS time.  OS is just a display clock.

It (the OS) is also the time management tool.

You may need to contact Dell Support if you believe this can be done. It is not so (quite sure) in my BIOS.

To clarify - I change the time and it goes right into boot with no option to save.

I think that is because they do not provide this facility in BIOS.

I hit Esc and it goes right into boot - no chance/option to save.

It's ESX, not Windows.

I thought ESX had a time module as well. I am going from recall but the virtual machines kept time and daylight savings correctly

Bill, make sure your CMOS battery is new.  I maybe low on power and can't hold new settings.

The real problem is that when we use Zerto to fail-over a VM to our DR site, Zerto uses the hardware
time of the DR host to set time in guest OS. BIOS time is UT 0 and we are UTC -10. VM time is consistently
10 hours ahead of HST.

You need to ask Dell if they have an update to support this.

I'd go with Tiras25 saying change the RTC/CMOS battery, after you change it you should get a time/date not set message during POST.

Bill, it's unusual that the BIOS is not allowing you to save the time before exiting to the POST, but since it appears the actual issue is Zerto needing the correct time, I'd approach that issue with a startup batch job that does

net time /setsntp:0.us.pool.ntp.org

Select allOpen in new window

which will set the time, hopefully, quickly enough after startup to avoid the Zerto issue.  Or alternatively, set the system time from your defined domain NTP source.   Then you can chase the BIOS issue at your leisure, or not at all if this is a solution.

Per Microsoft's commentary on manually setting time using NTP servers.

https://technet.microsoft.com/en-us/library/bb490716.aspx

We use a time server. When the host comes up it shows the screwy BIOS time colored red in Time Configuration, but quickly syncs to the NTP server. That's why our normal non-Zerted VM's never had a problem. Between the time I hit Esc and the time ESX fully loads, the BIOS time reverts.

As I suggested before I would contact Dell Support

Been my experience that BIOS  clock trumps software clock 100% of the time.

Thanks for the update.

Turns out they were setting the time on the iDRAC, not in BIOS. See https://www.experts-exchange.com/questions/29076812/Setting-hardware-time-zone-on-a-Dell-Poweredge-anymodel.html so Tiras25's answer was correct in how to save the time in BIOS - unfortunately they weren't in BIOS!

Relying on setting the time via the OS is just crazy, if you change a motherboard and don't set the time in BIOS and it's a Domain Controller then all hell can break loose.