In a HUS110 scenario, I note that you can change current controller that handles a volume, but this setting does not seem to 'stick'. What controls the behavior where another controller takes over handling a volume?
There is a feature called Load Balancing that moves volumes from a busy controller to a less busy controller. It is on by default which explains what you're seeing. You can turn it off under Performance > Tuning Parameters > System Tuning.
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