http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspxA few months Bruce Langworthy wrote an excellent article regarding some new recommendations for setting the Windows Disk Timeout value - http://blogs.msdn.com/b/san/archive/2011/08/15/the-windows-disk-timeout-value-understanding-why-this-should-be-seten-USTelligent Evolution Platform Developer Build (Build: 5.6.50428.7875)http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspx#3466450Mon, 21 Nov 2011 15:43:24 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3466450Neil Johnson<p>Mark, the primary concepts remain the same for Hyper-V, the main difference is that we are not working against a physical HBA or Raid controller to issue a bus reset to in the event of a problem. &nbsp;The timeouts for ESE remain the same though and if we hit the 4 minute mark we will still bugcheck the server, VM or Physical.</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3466450" width="1" height="1">http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspx#3466448Mon, 21 Nov 2011 15:41:13 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3466448Neil Johnson<p>Nuno, this sounds like you need to open a case with support. &nbsp;There are many reasons for a server becoming unresponsive, it not always storage related. &nbsp;If you take a look in the event logs you can typically see the ESE warnings about long I/O if that is what you are experiencing. &nbsp;In this instance it sounds like you may be experiencing something else.</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3466448" width="1" height="1">http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspx#3466254Sat, 19 Nov 2011 21:34:16 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3466254Mark<p>How does this apply to hyperv/vmware? </p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3466254" width="1" height="1">http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspx#3466067Fri, 18 Nov 2011 12:14:39 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3466067Nuno Mota<p>Really good article, thank you!</p> <p>Just a question: I am seeing this exact behaviour in one of my DAG members when I run backups on it. However, the server does not host any active databases (and you mentioned “(...) is affecting active databases on a DAG node”) and the server becomes completely unresponsive... It stops processing further backup jobs, unable RDP or login, but able to PING server... The only way of recovering is by rebooting the server using the VMware Console.</p> <p>If the server is hosting active databases, they don’t even failover to another DAG member...</p> <p>Is this the expected behaviour?</p> <p>Thank you!</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3466067" width="1" height="1">http://blogs.technet.com/b/exchange/archive/2011/11/17/windows-disk-timeouts-and-exchange-server-2010.aspx#3465965Thu, 17 Nov 2011 22:09:53 GMTd5e57398-b9ef-4490-9955-07cbb4e4a80d:3465965Dean Scully<p>Good read, howerver, the link here;</p> <p>If we go back to the reason I started out writing this article it was to assess if we should reduce the Windows Disk TimeOutVale on Exchange DAG server nodes as recommended ****here****</p> <p>Is to a local file.... are you able to fix that?</p> <div style="clear:both;"></div><img src="http://blogs.technet.com/aggbug.aspx?PostID=3465965" width="1" height="1">