Infrastructure at your Service

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Database Administration & Monitoring

Daniel Westermann

Which parameter changes do require a restart of my PostgreSQL instance?

By | Database Administration & Monitoring, Database management | 7 Comments

Starting wiht PostgreSQL 9.4 you can change parameters in postgresql.conf with the “alter system” command in psql. In principle every parameter can be changed that way but not every parameter is applied immediately. Some of the parameters require a reload others require a complete restart of the instance. But which of these parameter require what? How can you know which method you have to use for which parameter?

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Stéphane Savorgnano

SCOM: schedule group maintenance task with PowerShell

By | Database Administration & Monitoring, Operation systems, Technology Survey | 2 Comments

In my last blog post, here, I spoke about how to place SCOM group in maintenance mode. This script is really interesting with an integration in Windows Task Scheduler. At the end, the main purpose is to plan a maintenance window of our different servers. Let’s see how we can do that with PowerShell script. First, I try to use the cmdlet Register-ScheduledTask, which can be used to register a scheduled task definition on a…

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Stéphane Savorgnano

SCOM: change group state to maintenance mode with PowerShell

By | Database Administration & Monitoring, Database management, Operation systems, Technology Survey | No Comments

Some weeks ago, I wrote a blog post about the creation of SCOM groups in order to subscribe to alerts. Subscribe to alert is mandatory, of course, to be able to receive alerts concerning our group. But during operations like an update, a patching, …, we don’t want to be spoiled by lots of alerts. To avoid those unexpected Emails, we need to place our group and so, objects contained in this group, in maintenance…

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Oracle Team

EM 13c corrective actions

By | Database Administration & Monitoring | 2 Comments

With Enterprise Manager 13c, we have the possibility to define corrective actions. Let me show you how to use it. From the Enterprise Ă  Monitoring select Corrective Actions : Choose Add Space to Tablespace in the Create Library Corrective Action : Enter the name, a description and choose Metric Alert as event: Finally choose to Save to Library You have to publish your corrective action as it has been created as a draft version, you select Publish….

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Franck Pachot

Where is the ASM SPFILE?

By | Database Administration & Monitoring | No Comments

By Franck Pachot . In the previous blog post, to the question “where is the ASM SPFILE” I answered by running ‘asmcmd spget’. But this is available only if the ASM instance is started. If you have corrupted your SPFILE (and it’s easy to do it) you can start with a local PFILE and the CREATE SPFILE= FROM PFILE. But then you get the location of the local one you used. If you need to…

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Mouhamadou Diaw

Install Oracle 12c Flex Cluster Easily

By | Database Administration & Monitoring | No Comments

To install a flex cluster (or a flex ASM)  Grid Naming Service (GNS) is required. A GNS can be configured with dynamic public networks (DHCP) for VIP. This method is suitable for a big number of nodes.In this case GNS domain delegation is mandatory. In case of a few number of nodes, GNS can be configured without domain delegation. In this case we have to define manually all VIP addresses (like in a standard cluster)…

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Microsoft Team

Windows Failover Cluster : Introduction to paxos tag

By | Database Administration & Monitoring, Operation systems | No Comments

A couple of days ago, I was in charge to install a new SQL Server AlwaysOn and availability group with one of my colleague Nathan Courtine. During the installation, we talked about testing a disaster recovery scenario where we have to restart the Windows Failover cluster in forced quorum mode. Restarting a WSFC in such mode implies some internal stuff especially for the cluster database data synchronization between nodes. The WSFC uses internally the paxos…

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Franck Pachot

Extended clusters and asm_preferred_read_failure_groups

By | Database Administration & Monitoring | One Comment

By Franck Pachot . When you have 2 sites that are not too far you can build an extended cluster. You have one node on each site. And you can also use ASM normal redundancy to store data on each site (each diskgroup has a failure group for each site). Writes are multiplexed, so the latency between the two sites increases the write time. By default, reads can be done from one or the other…

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Franck Pachot

DB_FLASHBACK_RETENTION_TARGET may hang your database

By | Database Administration & Monitoring | 3 Comments

By Franck Pachot . DB_FLASHBACK_RETENTION_TARGET is set to keep enough flashback logs to be able to flashback database within the specified retention window. But it’s supposed to be a target only, meaning that on space pressure some files can be deleted. But be careful, there are cases where they are not and then the database hangs until you set a lower retention.

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