Category Archives: Availability

11g: handling error ORA-00752 – lost write of a data block in the PRIMARY database

With the recent (11gR1) addition of lost write detection techniques, Oracle has one more tool to help avoid data losses. Prerequisites to it are having a physical standby database applying logs and the parameters enabled in both the primary and … Continue reading

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ASM MEMBER disks showing as CANDIDATE

Some time ago I spent a few hours troubleshooting an issue where some 20 ASM member disks went all to either CANDIDATE or PROVISIONED status after the servers were rebooted. That’s odd because if the disks were really removed from … Continue reading

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Quick how-to: enable Active Data Guard

If you have the required additional license, with Oracle 11gR1 onward you can open your physical standby database for read-only operations. If correctly configured, it gives you the benefit of relieving the primary database from the burden of running those … Continue reading

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Quick script to start troubleshooting Data Guard gap/lag

Scenario: you are connected to the primary database and want to know if one or more of your standby databases are lagging behind? The script below will show the log sequences involved and even how many hours wide is the … Continue reading

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