We run multiple web servers in an infrastructure that makes use of a time service to synchronise the servers' datetimes. A particular web form that the web application displays has an 'AsAt' textbox that gets set using a DateTime.Now call when the page is rendered. A timestamp is written back to an Oracle database on insert or update as a 'Last Modified' field but using the Oracle sysdate function not the .Net DateTime.Now.
Recently, we have noticed that after a system time update by the infrastructure service this displayed datetime doesn't tie up with the current datetime of the system clock. The datetime corrects itself after an IIS reset.
The 'Last Modified' field calculated by the Oracle sysdate call is always correct.
From what we're seeing it would appear that IIS takes a copy of the current system datetime when it starts up. Does this sound right?