I helped one of my customer to sort this issue:

Action Plan:

• Copy the existing data from /storage/seat to /storage/core (or any volume) where we have 50 GB free space.
• Deploy a new vCSA of the same build and expand /storage/seat to 100 GB.
• Unmount /storage/seat from existing vCSA and mount /storage/seat from new vCSA to the existing one.
• Post this you will have to copy the data from /storage/core to /storage/seat.

Pre-requisite:

• Deploy a new vCSA with the same build.
• Stop vpxd service