One of the most common issues I look at from day to day is some variation of the question. “Why did it take a long time for my AG/Database to failover?”. There are many different meanings for this innocuously simple looking statement, for example was it that the failover time was long or was it […]
Departure Hopefully, you’re not finding this entry because you’re scouring the web for what reverting means while your production server is in this state… but chances are, that’s the case. Initiation What is reverting? How did I get here? Is this real life? All great questions. Each time a secondary replica connects to the primary, […]
I tend to be involved in many HA related issues, as is the nature of my current work agreement. The interesting part is that roughly 85% of all the “HA” issues are performance issues (with 10-12% being config issues and the last 3-5% being truly HA issues). Whether this is an FCI, AG, Replication, some […]
Be Careful What You Wish For Just a quick PSA as I’ve had a bunch of questions come up around this since the SQL 2019 CU9 release. You may see these types of items in your errorlog, they are benign. You can safely ignore them. Remember when you said, “Oh I wish I knew more […]
I Think My Knee Hurts, I Just Can’t Prove It Hopefully, you really do know if your knee hurts or not… it’d be odd if you weren’t sure. Regardless, this isn’t about knees but networks and specifically dealing with SQL Server Always On. I’m going to start out by stating that there are many improvements […]
On, Off, On, Off, On… I see this more often than I’d like to, so count this as your PSA (public safety announcement) when using VM level backup software, SQL Server, and even worse when you add in AlwayOn (FCI or AG). You might be familiar with these symptoms which may include: Unresponsive VMs Lease […]
I’ve been asked this question a few times, so I feel it’s worth writing about, which is, “Are Distributed Network Names (DNN) supported for SQL Server?”. The short version is, it’s not supported. The long version is, it’s not supported, but if you’re using a vanilla AG (not distributed) and aren’t using things like replication […]
I won’t say I told you so… I will, however, point out common AG question #8… I’m not sure why so many of these are coming up lately, but I’ve not had to troubleshoot a few, and I think it’s worth documenting this behavior. Let’s say you have Windows cluster which might have FCI’s, AG’s, […]
This is inspired by all the times I am forced to repeat myself. To cut down on hearing my own horrible sounding voice, I present to you a FAQ style post of all things Availability Group related that I am consistently asked. Last updated June 25th, 2020. Q1: What’s the limit of databases I can […]
Well That Escalated Quickly… Error 35217 translates to, “The thread pool for AlwaysOn Availability Groups was unable to start a new worker thread because there are not enough available worker threads. This may degrade AlwaysOn Availability Groups performance. Use the “max worker threads” configuration option to increase number of allowable threads.” which is fairly fatal […]
