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Comment by tw04 | Hacker News Reader

I'm surprised to hear that to be quite honest. The feature gap is still pretty significant for any serious production deployment. MS is working hard to close the gap, but given basic enterprise features like database mirroring still aren't there - I'm not sure why any large enterprise would shift at this point.

https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-...

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My understanding is that feature (database mirroring) was deprecated many years ago, for availability groups. There were some limitations in the Analytics area, but that customer was using another solution for most of that anyway. There were also some features of SQL Agent that were discarded (scheduling events or something) but in each case there is some officially supported route to accomplish the same task.

You can find most of the material we reviewed in the official MS documentation:

https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-...

For example, here's the note about deprecating database mirroring:

https://docs.microsoft.com/en-us/sql/linux/sql-server-linux-...

> Database mirroring, which was deprecated in SQL Server 2012, is not available on the Linux version of SQL Server nor will it be added. Customers still using database mirroring should start planning to migrate to availability groups, which is the replacement for database mirroring.

Availability groups are great on paper - in practice they add latency which many customers can't and won't tolerate. MS has been aware for years and still hasn't found a fix. Not sure hwy I'm getting downvoted - I'd assume people without SQL experience looking at a data sheet thinking it tells the whole story...

I believe you! The documentation says one thing, but in practice there are often hidden gotchas that can be extremely frustrating. Especially with respect to Azure, but even with the regular product. Microsoft has amazing sales teams, and some amazing engineers, but the overall quality of their engineering as delivered perhaps could use some work -- too much frustration, not enough delight.

> given basic enterprise features like database mirroring still aren't there

Database mirroring has been deprecated for several years. The replacement is Always On Availability Groups, which is vaguely supported on Linux.

MS WANTS customers to move to AGs but it introduces latency, which is why mirroring still exists in SQL 2019 and will indefinitely.

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