When I'm tried to enable option "shared=true" in custom persistance storage, nothing changes - all nodes updates storage (should update only node, that put cache entry).

This is part of documentation:
shared - (false by default) indicates that the cache loader is shared among different cache instances, for example where all instances in a cluster use the same JDBC settings to talk to the same remote, shared database. Setting this to true prevents repeated and unnecessary writes of the same data to the cache loader by different cache instances.