clean system data (oracle database)
Following, a useful sql request listing system tables sizes in descending order. It helps to detect which table data could be purged to save more disk space :
select owner, segment_name, segment_type, bytes / 1024 / 1024 "size" from dba_segments where tablespace_name = 'SYSTEM' order by "size" desc;
Audit table SYS.AUD$ could be the cause of full disk space. Administrator must control the growth and size of the audit trail.