• One of the main attractions of Dbvisit Standby is that it takes the complication out of setting up and running Oracle standby databases.

    Mike Meerding, Database Administrator, Australia

Disaster Recovery Solutions

Companies today rely on around the clock access to their data to support a wide range of users and external systems, including web-based self-service applications and integration with business partners’ systems. It is no longer acceptable for a failure of some component (hardware or software) to leave data unavailable at any time of the day or night.

This 24/7 operation requires reliable and timely disaster recovery (DR) mechanisms for all components of these solutions, including the databases. In the event of a failure, service must be resumed within a very short period of time, with minimal or no data loss.

The critical importance of DR is demonstrated by the following figures:

  • 43% of US businesses never reopen after a disaster and a further 29% close within two years (US Small Business administration)
  • 93% of companies that suffer significant data loss are out of business within five years (US Bureau of Labor)

DBVISIT STANDBY uses physical database replication to provide a cost-effective, reliable and proven DR solution for all Oracle databases, including Standard Edition.

Dbvisit Standby creates and maintains up-to-date copies of a production database that can be used in the event of a disaster. As changes are made to the production database, Dbvisit Standby applies these to the standby (backup) database at the remote DR site, creating an exact copy of the production database. In the event of a failure at the primary site, Dbvisit Standby is used to activate the standby site so it takes over the production role, and business continues uninterrupted.

The following diagram provides an overview of the data replication process performed by Dbvisit Standby, highlighting the three key steps in the replication process:

  • The extraction of logs at the primary site
  • The transportation of logs to the secondary site
  • The application of logs at the secondary site

Disaster Recovery Solutions with Dbvisit Standby

For more details, visit the Dbvisit Standby product page.

Dbvisit Standby is built on top of the tried and proven Oracle redo/archive logging mechanism, and provides a complete tool for delivering disaster recovery databases.

A Dbvisit Standby configuration consists of a primary (production) database and one or more standby (backup) databases. The primary and standby databases connect using a secure mechanism (SSH) over TCP/IP, allowing databases to exist anywhere provided they can communicate with one another via TCP/IP.

Once the standby database is available (and Dbvisit Standby includes tools to create this), Dbvisit Standby is scheduled to synchronize the databases by transmitting the archive logs from the primary database and applying them to each of the standby databases.

Oracle archive logs are periodically picked up, optionally compressed, and transferred securely to the standby databases.  The frequency of this transmission is determined by configuration, with the processes on the primary and standby sites independently scheduled, providing a high degree of control over when data is extracted and when it is applied.

In the event of communication failure, logs are accumulated at the primary site until Dbvisit Standby determines that the network connection has been re-established.  Once this happens, Dbvisit Standby transmits the available updates to the secondary sites in the correct sequence.

Replication monitoring sends alerts when it identifies exceptions outside of the configured acceptable bounds, providing advance warning to operators of a failure or disaster.  Once failure of the primary site is identified, a single command on the standby server is all that is required to force it to take over as primary database. 

Dbvisit Standby assists with the recovery process, providing tools that enable the creation of new databases from the operational production database.  This process is highly automated and can be used to quickly establish new standby databases at one or more sites.

Graceful switchover is used to switch roles, transitioning the production database (operating at the standby site during DR operation) to a standby database and the standby database (newly created at the primary site) to the production database.  There is no loss of data during the transition and the standby database does not have to be rebuilt

Maintaining your database and protecting it against failures is an essential part of the DBAs job. Without the right tools it can prove to be the most unproductive part of it too. Because Dbvisit Standby gives you control over your database environment it makes managing it less of a chore and frees up more time to focus on other activities. Additionally, the savings on license costs and maintenance fees are significant (up to 80%), as there is no need to upgrade to Enterprise Edition to utilise Data Guard and Dbvisit Standby requires you to license only the primary server.

Dbvisit Standby provides disaster recovery for Oracle databases by creating a copy of the original database using a technique known as physical database replication.

Changes are applied at the lowest (binary) level available within the database, ensuring that the standby database is an exact replica of the primary database, including all internal database indexes, pointers and tables.

Physical replication incurs the lowest overhead and provides a 100% guarantee that the standby database (or databases) is consistent with the primary database. There is no restriction on the types of data that can be replicated, and the complexity of maintaining consistency and completeness is handled entirely by the database. Finally, the exacting nature of the replication ensures that applications relying on internal data fields, such as index values and generated foreign keys, will operate correctly on the replicated database.

What is a standby database? Read more here.

 

 

Alex Gorbachev Pythian CTO - Dbvisit Standby Case Study
 
Dbvisit Whitepaper: using Physical Replication and Oracle Database Standard Edition for Disaster Recovery

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Businesses in over 80 countries worldwide with Oracle® Database Standard Edition trust Dbvisit to protect and share their data.

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