Database backups and transaction log files

In a cold site recovery, the database has to be restored to the last successful backup and the transaction logs replayed to update the database with all the changes performed since the backup.

Given the importance of these files, many companies copy these files for off-site storage. In some cases, transaction logs are immediately copied to a remote site when the logs are closed.

Standard copy utilities can only copy files that are not opened for access. If you rely on standard copy utilities, you can not backup the currently active (and open) transaction log.

For warm and hot sites recoveries, you could use log-shipping technologies to not only replicate but also to apply the log transactions to the standby database.

For Oracle, you could use products such as Oracle Data Guard or Quest Shareplex.

For Db2®, you could use Db2 HADR. However, with HADR, you can replicate to only one standby database. If you want to have a standby Db2 database server at the local site and the disaster recovery site, you may have to use a combination of cluster failover software and HADR respectively.