Major Description
Shutdown and startup will hang if their regions and parallel gateway disk stores are separated from each other. They need to be grouped together same as colocated regions. Disk store can differ for serial gateway senders, but parallel ones must be colocated with the regions they are attached to, and colocated regions must be stored in the same disk store to not cause synchronization issues.
The resolution is to either have one disk store for all gateway senders and regions or group regions and gateway senders logically together in disk stores so each region and its gateway senders are in a particular disk store.
Document this behavior and the solution.
