The user can set default journal parameters (number of files and a size of each file) in qpidd config file. These are the options 'num-jfiles' and 'jfile-size-pgs', which are properly documented. The broker is supposed to use these parameters while creating a new durable queue in case that no journal parameters were provided by the client's application.
The problem is that qpid-config tool sends values fileCount = 8, fileSize = 24 to the broker if called without "-
file-count" and "-file-size" parameters.
Imagine the situation where a user sets some default 'num-jfiles' and 'jfile-size-pgs' values in qpidd config file and then creates a durable queue using qpid-config tool: 'qpid-config add queue test --durable'. The resulting queue's journal will have parameters fileCount = 8, fileSize = 24, which will differ from the ones set by the user in config file.