A key requirement is getting the DiskTimeOut value in the Windows registry updated to 60 seconds, default is 30.  How to do this is covered in the "OS considerations guide.." located with the Firmware downloads.  You have to select a FW rev first then you'll see links for all the documentation.   Note a reboot is required to make the change effective.  There's also settings for Linux in there as well.   ESX has a default timeout that's already set but ESXi v5 needs to have the Login timeout changed from 5 to 60 seconds. See VMware KB 2007680 kb.vmware.com/.../2007680.  ESX v4.1 will in the fugure have a patch to allow that login timeout value to be changed from 15 to 60 seconds as well.   One thing I have seen is that some applications have their own timeout value, and don't wait for the disk timeout to expire before they error and possibly stop.  Applications like SQL and Exchange can be the most sensitive.   Some customers will shutdown SQL and Exchange right before doing the restart to prevent any possible problem with those apps.   Doing this after hours/low IO times is suggested.   The more IO and connections you have the longer the failover and re-login process might take.   Hope this helps. 
Hi folks, we are having a standalone PS6000 storage. Its firmware version is 5.2.1. The storage is a part of a Hyper-V failover cluster. In the past we stopped all virtual machines before upgrading the firmware, but not the cluster nodes. It meant service downtime and all the fun related to service interruption.  Could you please share your experiences in upgrading firmware for PS6000? What is your strategy: do you shutdown virtual systems as we do? Or don't you stop all virtual systems but only the sensitive ones like MS SQL servers? Or do you stop no virtual machines and upgrade your storage absolutely live? Thank you in advance! Kind regards, Hermann Maurer
PS6000: Firmware upgrade experiences