Ok I am getting closer, in ESX4 it can resignature the volume when it is scanned and this can cause the problem. So what I have done I have disabled this feature on the ESX4 servers from the console using this command esxcfg-advcfg -s 0 /LVM/EnableResignature on ESX3.5 servers this can be done in the configuration, advanced settings or from the console using the same command.

The result is that on a reboot one server show both paths to volume are ok the second server shows they are broken if I then do a rescan all on that server it restores the paths to show ok.

I need to find out if there is a way of getting it to automatically rescan after it reconnects the volume. Any vmware guys out there that would like to provide assisatnce please do.

Gavin