hadbm set brings the database instance to a state that is hard to recover from.
Changing a database configuration variable with the hadbm set command fails. For example, setting DataBufferPoolSize to a larger size fails due to lack of shared memory on node-0. The hadbm set command leaves the database with node-0 in a stopped state and node-1 in a running state. Resetting the pool size back to the original value with the help of hadbm set fails with the message:
22073: The operation requires restart of node 1. Its mirror node is currently not available. Use hadbm status --nodes to see the status of the nodes.
The hadbm startnode 0 command is also of no use in this situation.
Stop the database, then restore the old values using hadbm set, then restart the database.