Infrastructure at your Service

Cluster Archives - Page 2 of 3 - Blog dbi services

David Barbarin

SQL Server 2016: Distributed availability groups and Cross Cluster migration

By | Database Administration & Monitoring | 2 Comments

How to migrate an environment that includes availability groups from one Windows Failover Cluster to another one? This scenario is definitely uncommon and requires a good preparation. How to achieve this task depends mainly of your context. Indeed, we may use a plenty of scenarios according to the architecture in-place as well as the customer constraints in terms of maximum downtime allowed for example. Among all possible scenarios, there is a process called “cross-cluster migration…

Read More
Oracle Team

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…

Read More
David Barbarin

Windows Server 2016: Introducing Storage Spaces Direct

By | Hardware & Storage, Operation systems | 5 Comments

Have you heard about Storage Spaces introduced by Windows Server 2012? Well, this is a very interesting storage feature that allows us to deal with functionalities like storage virtualization, RAID capabilities, thin or thick provisioning, cluster shared volume (CSV), efficiently file repair and so on. In addition, the Windows 2012 R2 version has also introduced some enhancements like storage tiering, write-back caching, datadeduplication, parity space support for failover clusters, JBOD enclosure awareness… A bunch of…

Read More
David Barbarin

Windows Server 2016: Introducing stretch cluster functionality

By | Database Administration & Monitoring, Hardware & Storage | One Comment

Let’s continue with the new high available functionality shipped with the next Windows version. In my previous blog, I talked about the new site awareness feature that provides more flexibility to configure failover resources priorities and more granular heartbeat threshold as well by introducing the new site concept. This time, we’ll talk about stretch cluster. What’s that? Let’s introduce the concept with some customer experiences for which we introduced high availability with the implementation of…

Read More
David Barbarin

SQL Server AlwaysOn and availability groups : how to isolate the replication traffic from other networks?

By | Database Administration & Monitoring | 12 Comments

A couple of days ago, I was involved in a project about implementing availability groups with SQL Server 2014. My customer wanted to isolate the replication traffic from the public network. The idea behind was to get a better control of the network bandwidth as well as to be sure that the replication can be done without any latency issues in case of heavily network traffic issued by other applications or backup activities for instance….

Read More
Daniel Westermann

ACFS 12.1.0.2 on Oracle Linux 7.1

By | Database Administration & Monitoring | 2 Comments

Recently we wanted to create an ACFS filesystem on a brand new 12.1.0.2 GI installation on Oracle Linux 7.1. According to the documentation this should not be an issue as “Oracle Linux 7 with the Unbreakable Enterprise kernel: 3.8.13-33.el7uek.x86_64 or later” is supported. The “or later” is the important point. In our case: uname -a Linux racp1vm1 3.8.13-55.1.6.el7uek.x86_64 #2 SMP Wed Feb 11 14:18:22 PST 2015 x86_64 x86_64 x86_64 GNU/Linux   Should be fine as…

Read More
David Barbarin

SQL Server 2016 : availability groups and load balancing features

By | Hardware & Storage | 8 Comments

Let’s continue with this third post about SQL Server AlwaysOn and availability groups. Others studies are available here: New database issue level detection for automatic failover Potential features in standard edition Automatic failover enhancements   This time I’ll talk about read-only secondaries and the new load-balancing support that will be introduced by SQL Server 2016. First of all, SQL Server 2014 improved the read-only secondary availability by solving the issue related to secondary accessibility when…

Read More
David Barbarin

Windows Cluster vNext and cloud witness

By | Operation systems | No Comments

The next version of Windows will provide some interesting features about WFSC architectures. One of them is the new quorum type: “Node majority and cloud witness” which will solve many cases where a third datacenter is mandatory and missing to achieve a truly resilient quorum. Let’s imagine the following scenario that may concern the implementation of either an SQL Server availability group or a SQL Server FCI. Let’s say you have to implement a geo-cluster…

Read More
Alain Lacour

High availability in the Oracle landscape

By | Hardware & Storage | No Comments

It’s now several weeks I attended some event about high availability (HA). But what is actually high availability? According to our friend Wikipedia, HA is based on 3 main principals: Elimination of Single Point of Failure (SPoF) Reliable crossover (with minimal or no downtime) Detection of failures when they arrive If those principals are met, end users may never realize about a failure. The aim of that blog is not to dive into too much…

Read More