When trying to create a new partition in Storage Manager the new partition is not saved when pressing Save Changes.
A customer's storage partition was becoming full. They created a new partition, but forgot to assign the ownership to tomcat
chmod -R 774 /data/retainarchive2
but that was only part of the issue, because the new partition still would not save in Storage Manager.
Checking the RetainServer log we found that it was attempting to backup ASConfig but failing.
It turned out the ownership of ~/RetainServer/WEB-INF/cfg/cfg_bku was no longer tomcat. Setting them as above resolved the issue. This directory is not a standard directory in Retain 3.x systems.