appropriate in such a case. Active Data Guard The "Oracle Active Data Guard" option, an extra-cost facility, extends Oracle Data Guard functionality in Oracle 11g configurations. It allows read-only access on the Physical standby node at the same time as applying archived transactions from the primary node. Also it features Automatic Block Repair and Fast Incremental Backup on Physical Standby, Operation Server-side functionality LNS (log-write network-server) and ARCH (archiver) processes running on the primary database select archived redo logs and send them to the standby-database host, where the RFS (remote file server) background process within the Oracle instance performs the task of receiving archived redo logs originating from the primary database and writing them to a standby redo log (SRL). Alternatively, a supplementary mechanism may transfer the archived redo logs. On the standby database a Fetch Archive Log (FAL) client monitors for gaps in the sequence of received logs. If it finds a gap, it may invoke one or more Fetch Archive Log (FAL) servers to run on the primary database to forward the missing item(s). Once the archived redo logs have arrived on the standby host, other processes - such as an ARCH (archiver process), an MRP (Managed Recovery Process), and/or an LSP (Logical Standby Process) - may set about applying the log contents to the standby database. The use of standby redo logs can speed up the application of changes to a standby database with real-time apply. The Data Guard Connection process (DRCX) plays a role in transferring data between databases. Client-side access The Data Guard Broker subsystem can aid in the setup, management and monitoring of Data Guard configurations. Advantages Data Guard provides high availability for a database system. It can also reduce the human intervention required to switch between databases at disaster-recovery ("failover") or upgrade/maintenance ("switchover") time. Through the use of standby redo log files, Data Guard can minimize data loss. It supports heterogeneous configurations in which the primary and standby systems may have different CPU architectures, operating systems (for example, Microsoft Windows and Linux), operating-system binaries (32-bit/64-bit), or Oracle database binaries (32-bit/64-bit). Disadvantages If the network link connecting primary and standby is over-subscribed, the redo logs are not shipped in chronological order, which can result in large gaps appearing in the available redo at the standby. Such a condition results in the standby being behind the primary. This can be overcome, using Oracle’ Active Data