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disaster recovery

SQL Server Always On Availability Groups and Database Master Keys: A Hidden Failover Pitfall

I recently came across an interesting case involving a client whose application used SQL Server symmetric keys to encrypt sensitive data. The database was hosted in an Always On Availability Group environment for high-availability and disaster-recovery. The interesting and challenging aspect of this setup is ensuring that the encryption and decryption remains intact after a failover. This challenge originates from… 

dbvisit StandbyMP with Oracle SE2 – ERROR_CODE:808 Database in unknown mode (94). Setup cannot proceed.

I recently deployed a new installation at one customer with 2 linux servers and 2 Oracle SE2 databases with dbvisit StandbyMP v11 disaster recovery solution. I prepared the standby database using RMAN duplication method, and then just wanted to create the dbvisit DDC configuration using CLI command. I had to troubleshoot one error, and wanted to share quickly the solution… 

Lost access to SQL Server. Now what ?

In this blog we will explain what to do to regain the access to your SQL Server instance. Here is our scenario : – You have by accident removed all logins in SQL Server instance – Your sa account by security and best practice is disabled – So no possibility to login with a sqlcmd or your SSMS (SQL Server… 

5 things that aren’t true about RMAN

Introduction RMAN backups are not a hot topic today. This is because it didn’t evolve that much in 12c/18c/19c, and most of the databases are now protected by a good backup strategy since years, and no changes are needed. Furthermore, Disaster Recovery solutions are more and more deployed, and all the flashback technologies embeded in the database are well known.… 

Configure Data Guard with odacli on ODA

Introduction I always thought integration of Data Guard was a missing feature on Oracle Database Appliance. For sure, you can configure Data Guard manually as you do on a classic server, but as an appliance, ODA should have proposed an easier way for configuring that. After years of waiting for this feature, it’s now available, and I just tested it.… 

dbvisit dbvctl process is terminating abnormally with Error Code: 2044

When applying archive logs on the standby, dbvctl process can terminate abnormally with Error Code: 2044. This can happen in case there are several archive logs with huge size to be applied. Problem description With dbvisit there is 2 ways to recover the archive log on the standby, either using sqlplus or rman. By default the configuration is set to… 

Speaking at the next SQL Nexus at Copenhagen 2017

On May 2nd, I will have the chance to speak during the next SQL Nexus event in Copenhagen (1 -3 may) about SQL Server 2016 and availability groups and if I have enough time, you will see what is coming with the SQL Server vNext. This is also a good opportunity to attend to other sessions held by well-known people… 

SQL Server AlwaysOn – Distributed availability groups, read-only with round-robin capabilities

This blog post comes from a very interesting discussion with one of my friends about the read-only capabilities of secondary replicas in the context of distributed availability groups. Initially, distributed availability groups are designed to address D/R scenarios and some migration scenario types as well. I already discussed about of one possible migration scenario here. However, we may also take… 

Introducing high-availability and multi-subnet scenarios with SQL Server on Linux

On my first blog about SQL Server on Linux, I introduced the new high availability feature which concerns only SQL Server failover cluster instances so far. During this discovery time, I had the support of Mihaela Blendea (@MihaelaBlendea) at Microsoft to clarify some architecture aspects about this new kind of architecture. Firstly, I would like to thank her. It’s always a… 

MS Cloud Summit Paris 2017

Une nouvelle année commence et 2017 devrait être un bon cru dans le domaine de la base donnée notamment en prédiction des effets d’annonces faites par Microsoft cette fin d’année 2016. En effet, il a été notamment été question de la prochaine vNext de SQL Server qui sera porté sous Linux ainsi que des nouvelles fonctionnalités prometteuses. A l’habitude, l’équipe dbi services tentera couvrir… 

SQL Server 2016 AlwaysOn: distributed availability groups

This time, I will talk about distributed availability groups. What’s that? In short, a group of availability groups. Sounds good right? But in which cases may we need such architecture? Firstly, let’s say that distributed availability groups will run on the top of two distinct availability groups meaning that they reside on two distinct WSFCs with their own quorum and… 

SQL Server AlwaysOn: is my database ready for failover?

In this blog post I just want to clarify values that we may find from the is_failover_ready column of the sys.dm_hadr_database_replica_cluster_states DMV. A couple of days ago, I had an interesting discussion with one of my customers during which he explained he was not confident about the availability group state after facing some unavailability issues. The main source of uncertainty…