title: SQL Server stops responding and server freezes
body: <p>we have a 2008 SQL Server machine, for some reason which we still havent figured out, every two weeks this server stops responding around the same time and around the same day, it's either sunday or saturday, we have checked the logs and the only message we have found is this </p>
  
  <blockquote>
    <p>A significant part of sql server process memory has been paged out.</p>
  </blockquote>
  
  <p>On the operating system log we algo found a message </p>
  
  <blockquote>
    <p>Application popup: Windows - Virtual Memory Minimum Too Low : Your system is low on virtual memory. Windows is increasing the size of your virtual memory paging file. During this process, memory requests for some applications may be denied. For more information, see Help. </p>
  </blockquote>
  
  <p>so it looks like the operating system is out of physical memory, we do not undestand why this happens every two weeks, it seems as if memory never gets freed and two weeks is the period it takes to get full. Is there a way we could better diagnose this? we are also wondering if it is related to how we are using NHibernate? or is there any other cause?</p>