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David Barbarin

SQL Server 2014: Availability groups failover impossible with Failover Cluster Manager

By | Hardware & Storage | 2 Comments

A couple of weeks ago, I worked for a customer that wanted to implement SQL Server 2012 (and not SQL Server 214) AlwaysOn with availability groups. During our tests we performed a bunch of failover tests and the customer tried to perform a failover of one of the installed availability group by using the failover cluster manager (FCM). Of course, I told him this is not best practice because the failover cluster manager is not…

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Stéphane Haby

SQL Server 2014: AlwaysOn-Verfügbarkeitsgruppen – jetzt mit Microsoft Cloud!

By | Database management | No Comments

SQL Server 2014 bietet jetzt (oder bald :roll:) die Möglichkeit der Integration von AlwaysOn-Verfügbarkeitsgruppen mittels virtueller Maschinen, gehostet in der Windows-Azure-Infrastruktur (IaaS). Sie können sekundäre Datenbanken direkt in der Cloud vorhalten, wie das Beispiel zeigt: Der Einsatz von asynchroner sekundärer Replikation in der Cloud ist durch die Integration des Assistenten in SQL Server Management Studio (SSMS) erleichtert worden. Was sind die Vorteile dieser Entwicklung? Der erste Vorteil ist Kostensenkung, wenn Sie Ihre Hochverfügbarkeitslösung erweitern wollen….

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Stéphane Savorgnano

High availability and disaster recovery on Windows Azure VMs

By | Technology Survey | No Comments

To be honest, I am not a specialist of Windows Azure. In order to learn a little bit more about this subject, I decided to follow a TechEd Europe 2013 session about High Availability and Desaster Recovery on Windows Azure Virtual Machines. Overview of Windows Azure Windows Azure is Microsoft’s application platform for the public cloud. You have the possibility to use this platform in many different ways: build a web application that runs and…

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Oracle Team

Oracle RAC A disturbing loop in a “ohasd” startup script

By | Operation systems | No Comments

Last February, I performed an operating system rolling upgrade on a four-nodes RAC cluster ( I then faced a strange problem when restarting the operating system… The first step of the procedure was to stop all Grid Infrastructure and Database services running on the first node as well as to disable Cluster and ASM autostart. The following command is supposed to prevent Oracle High Availability Service (OHAS) to be run at operating system startup: #…

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Gérard Wisson

Oracle Middleware, administration and monitoring: a day at the DOAG SIG Middleware

By | Application integration & Middleware | No Comments

I am in the train back to Basel (Switzerland) and I will try to summarize the day spent on a SIG Oracle Middleware of the DOAG (German Oracle User Group) session related to Oracle Middleware administration and monitoring. The different topics I saw were: WebLogic 11g clustering and high availability Overiew of the Cloud Control 12c (monitoring, automatization, quality management, cloud management Real User Experience Insight (RUEI): End-to-End User Monitoring and Java Diagnostic Administration and…

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Stéphane Haby

Stéph@TechEd 2012: Episode 1 – the Pre-Conf. Seminar

By | Technology Survey | No Comments

This morning, I was very happy to go to my first TechEd. Between the 10 seminars, as I said yesterday, I started with SQL Server 2008R2/2012 performance, tuning and optimization session. The thing is that we had just one session for the whole day. I will not copy the presentation of the 2 speakers (Thomas LaRock and Denny Cherry) who presented remarkably this session despite the failure of air conditioning during the morning. Fortunately, it…

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Grégory Steulet

MySQL Data High Availability with semi-synchronous replication

By | Hardware & Storage | No Comments

Starting with MySQL 5.5 it is possible to configure semi-synchronous replication. As you probably know, by default, MySQL replication is asynchronous.  Asynchronous replication means that events/transactions applied on one server are not immediately applied on the other one. In the specific context of MySQL such behavior means that the MySQL Master writes transactions/events to the local binary logs, however it has no idea when the slave(s) will get and process them. Of course such configuration can lead, in case of failover, to some transaction loss since there is no guaranty that the transactions have been transmitted on the standby server(s).

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