i svmotioned a bunch of vms from one san to another san. then afterwards, disconnected the san. the vms on the temp luns continued to run fine but after a while all the hosts and luns shows disconnected. i could still ping the hosts and vms but they were not manageable within vcenter.
then finally i had to shutdown all vms and reboot the host.
in the vmkernel log, it was showing a lot of dead paths which should be the disconnected luns from the san upgrade.
how do I avoid this?
On certain versions of ESX (4.0 prior to U2 and 4.1 prior to U1) if you have an APD (all paths down) condition, this could lead to this behavior. The newer versions don't have this problem. What version are you using?