Failure with loss of Nonvolatile Storage
The basic measure is to dump the entire contents of the database to stable storage periodically.
One approach to dump the database requires that no transaction is active during the dumping procedure and uses a procedure similar to checkpointing.
a) Output all the log records currently present in the main memory into the stable storage.
b) Output all the buffer blocks into the disk.
c) Copy all the data present in the database to the stable storage.
d) Output a log record <dump> into the stable storage.
A dump of the database contents is also called the ‘archival dump’.
Most database systems support an ‘SQL dump’ as well, which writes out all the SQL DDL statements and SQL insert statements into a file, which can then be re-executed to recreate the database.