Free disk space unchanged after classic resize

One scenario that could result in the behavior described is if there is a large number of small tables that have a distribution style of EVEN/ KEY. If that is the case, then changing the distribution style for these smaller tables to ALL may help reclaim some space. Each table on Amazon Redshift has a minimum table size and this varies based on the number of columns, the number and type of the nodes in the cluster and the distribution style. The below link has more information on the topic and illustrates how this works using a few examples: https://aws.amazon.com/premiumsupport/knowledge-center/redshift-cluster-storage-space/