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SQL Server 2016 AAG HADR Endpoint possible contention?

  • September 25, 2018 at 8:57 am

    #368811

    By default, a SQL Server instance will have a single hadr endpoint on port 5022.
    On an AAG setup consisting 19 AAGs (>70 databases, 19 Applications). Some of these include SharePoint, SCCM and several transactional line of business applications.

    1. Besides an obvious concern for having too much on a single SQL server, can the fact that all AAGs point to a single endpoint on each SQL instance introduce contention?
    2. This design was to also to have all AAGs use synchronous replication between the local datacenter (2 servers) and 1 remote DR server. Are the improvements in SQL Server 2016 substantial enough that it would be possible to use synchronous replication and not slow down the primary instances while the secondary instances catch up?

    I've illustrated the potential issue below.

  • September 25, 2018 at 10:04 am

    #2006944

    I think that the endpoint would be fine. What I would be concerned about is having a synchronous replica on a remote site. Your round trip commits are going to slow down the primary. The primary doesn't commit until all secondary synchronous replicas commit. If your business is okay with that, then more power to you. I would do some testing. But typically, for my business, I have 2 servers in the same rack on prem that are synchronous. I have 2 other servers both at different sites across the country that are asynchronous so they do not slow down the primary. Finally, we have log backups every minute and log restores every day on different instances around the country to strengthen the DR.

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