SQL Server Read-Only Routing

Not too long ago, I had a conversation with a friend about how SQL Server Always On Availability Groups and how they could be configured for Read-Only routing. This is a typical scenario when folks want to leverage their secondary replicas (nodes) for read-only workloads. This allows you to build an active-active cluster where one…

SQL Server Always On – Monitor The Redo_Queue_Size

Cause sometimes you need to check why replication is slow or halted. For example, like during an IO storm - no hurricane pun intended. Say you have transnational replication over an Always On (SQL Server Availability Groups) environment that's a publisher. To see in the Dashboard just add the column, this is what it looks…

SQL Server 2017 – Deferred Name Resolution Bug.

This issue came up recently while in the midst of an upgrade to SQL Server 2017, but it's actually not related to the upgrade and has been around all along on previous versions. So I took a moment to write this, cause a friend told me it would make a nice blog post. Mad credit…

SQL Server 2016 AlwaysOn in Windows Server 2012R2 WFC – MultiSubnet Listener returns wrong IP address after a FlushDNS – Error Connection Timeout!

Issue: (Failover had not occurred, commands executed without pause).   Fixed. Key changes were RegisterAllProvidersIP=0, HostRecordTTL=300 (5 minutes instead of default 1200 (20 minutes)). If using .Net Framework 4.5+, recommend adding to client connection strings: MutiSubnet=True; Ref SqlClient support for HA and DR. Key steps were: Set RegisterAllProvidersIP=0 for the Cluster and LG. Set HostRecordTTL=300 (5 minutes instead of default…