availability

Cloud Storage Replication Is Not Backup

The options that you need to select when setting up an Azure Storage service account allow you to specify the durability and high-availability of your data, but they don't provide for data recovery to a point-in-time. In fact, it means that some of the bad things that can happen to data are more efficiently replicated to all copies. Backup is quite a separate issue.… Read more

A first look at SQL Server 2012 Availability Group Wait Statistics

If you are trouble-shooting an AlwaysOn Availability Group topology, a study of the wait statistics will give a pointer to many of the causes of problems. Although several wait types are documented, there is nothing like practical experiment to familiarize yourself with new wait stats, and Joe Sack demonstrates a way of testing the sort of waits generated by an availability group under various circumstances.… Read more

SQL Server 2012 AlwaysOn

SQL Server AlwaysOn provides a high-availability and Disaster-recovery solution for SQL Server 2012. It makes use of existing SQL Server features, particularly Failover Clustering, and provides new capabilities such as availability groups. Warwick Rudd explains the basics and shows you how to implement it.… Read more

Database Properties Health Check

Within an instance of SQL Server, the database settings can have a direct effect on the database's behavior, performance and availability. Sometimes, it is difficult to tie a symptom to a cause, so it is wise to routinely check and record these settings. Before you change the current setting, it pays to understand exactly what it means and the implications of any change.… Read more

The One Way That High Availability Will Help You

High Availability (HA) is a term that is beloved of the marketing people, with its connotations of an unspecific sense of reassurance. However, service reliability cannot be bought like bath salts: But, explains a seasoned and cynical expert in the field, HA can be more than the start of 'HAHA!'. There is a role for HA in keeping your services running, if used as part of a broader solution.… Read more

7 Things that High Availability is Not

Wesley has heard High Availablity touted as all sorts of technological cure-all for busy SysAdmins and DBAs, and now he's taking a stand against it. There are a range of things that High Availability is regularly confused with (either deliberately or innocently), and Wesley's clearing it all up.… Read more

Exchange 2010 DAG Creation and Configuration Part 1

If you're using Exchange 2010, then you're probably interested in using the new Database Availability Group feature for your High Availability needs. The DAG is superbly powerful technology, but you'd better make sure yours is 100% correctly configured. Neil Hobson walks us through what we need to know, using a two-node DAG as an example.… Read more

Increasing the Availability of Virtualised Applications and Services

By using a virtualized clustering computing environment with failover, you can improve server availability without using as many physical computers. A group of independent computers can work together to increase the availability of virtualised applications and services. If one of the cluster nodes fails, another node takes over to provide the service without disrupting the service. Nirmal Sharma explains the failover process under Hyper-V and how to improve the performance of a failover.… Read more