According to certain aspects, a client computing system can be configured to map stored database data into a plurality of second data units having a second level of granularity larger than first data units; store a mapping of the second data units to the first data units; monitor writes to the database data by the database application; identify of the writes changed first data units of the first data units which have changed as a result of the writes; use the mapping to identify changed second data units of the second data units which each include at least one of the changed first data units; maintain a table listing the changed second data units; and in response to instructions to create a secondary copy of the database data, consult the table to identify the changed second data units, and forward the changed second data units to secondary storage controller computer(s).