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#Exasol Fail-Safety explained

The building blocks of an Exasol cluster are commodity Intel servers like e.g. Dell PowerEdge R740 with 96 GB RAM,12 x 1.2 TB SAS Hot-plug hard-drives and 2 x 10Gb Ethernet Cards for the private network. That’s sufficient to deliver outstanding performance combined with high availability. The picture below shows a 4+1 cluster, one of our most popular configurations:

Foreign Archived Log in #Oracle – what does it mean?

When you look into V$RECOVERY_AREA_USAGE, you see a strange row at the bottom:

Let the Data Guard Broker control LOG_ARCHIVE_* parameters!

When using the Data Guard Broker, you don’t need to set any LOG_ARCHIVE_* parameter for the databases that are part of your Data Guard configuration. The broker is doing that for you. Forget about what you may have heard about VALID_FOR – you don’t need that with the broker. Actually, setting any of the LOG_ARCHIVE_* parameters with an enabled broker configuration might even confuse the broker and lead to warning or error messages. Let’s look at a typical example about the redo log transport mode. There is a broker configuration enabled with one primary database prima and one physical standby physt. The broker config files are mirrored on each site and spfiles are in use that the broker (the DMON background process, to be precise) can access:

Don’t go directly to Maximum Protection!

With a Data Guard Configuration in Maximum Performance protection mode, don’t go to Maximum Protection directly, because that leads to a restart of the primary database:

 Attention!

Simora: Alpha Testers Confirmed

It’s been a while since I provided any public updates regarding Simora, our Oracle workload simulation product. It’s finally time to unveil the status of Simora and our steps moving forwards. We have been working extensively on the Simora engine and infrastructure over the  last several months, with a view to transforming it into a … Continue reading "Simora: Alpha Testers Confirmed"

Simora: Alpha Testers Confirmed

It’s been a while since I provided any public updates regarding Simora, our Oracle workload simulation product. It’s finally time to unveil the status of Simora and our steps moving forwards. We have been working extensively on the Simora engine and infrastructure over the  last several months, with a view to transforming it into a … Continue reading "Simora: Alpha Testers Confirmed"

Simora: Alpha Testers Confirmed

It’s been a while since I provided any public updates regarding Simora, our Oracle workload simulation product. It’s finally time to unveil the status of Simora and our steps moving forwards. We have been working extensively on the Simora engine and infrastructure over the  last several months, with a view to transforming it into a … Continue reading "Simora: Alpha Testers Confirmed"

HA of Database Control for RAC made easy

When you install an 11g RAC database without Grid Control respectively Cloud Control present, this is what the DBCA will give you:

RAC_dbconsole1There is one Database Control OC4J Container only, running on host01. Should host01 go down, the Enterprise Manager is no longer available now. We could make that a resource, known to the clusterware and let it failover in that case. But also – and even easier – we can start a second OC4J Container to run on host02 simultaneously like this:

System Architecture Series: Introduction to the Series and Licensing

This blog post is an introduction to a few posts that can be grouped together under the banner of 'System Architecture'. Specifically, I'm referring here to Oracle Database System Architecture, not system architecture in general nor 'Oracle architecture' in general, which is an ever-growing beast. In this series of posts, I will take at look […]

System Architecture Series: Introduction to the Series and Licensing

This blog post is an introduction to a few posts that can be grouped together under the banner of 'System Architecture'. Specifically, I'm referring here to Oracle Database System Architecture, not system architecture in general nor 'Oracle architecture' in general, which is an ever-growing beast. In this series of posts, I will take at look […]