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Comment by tw04 | Hacker News Reader

SQL? There are literally millions of production SQL databases out there and custom apps built on top of them - and while MS may have created a Linux port, there's no planet on which the average enterprise is moving to SQL on Linux without VERY good reason (and there currently isn't one that I can see outweighing the risk).

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A company I consult for specializes in SQL Server applications. There is a significant push to Linux from both the largest customers, paying over 150k$/month for server licensing and hosting, and from the smallest companies, who are severely budget-conscious. The big customers have teams fluent in both Linux and Windows, and the smallest outsource their DBAs and sysadmins, so in both cases the cost is mostly a one-time development cost and maintenance goes on as usual.

The medium-sized enterprises (100MM$ to 500MM$ annual revenue) are the ones who aren't looking at Linux. These are the ones with in-house tech support, who only know Windows. Maybe they are the average customers that won't switch over?

Note that I'm only talking about cloud-hosted SQL Server installations. When you're buying the whole infrastructure stack, it's a different story. Also, this isn't the area I specialize in, so this is just a narrow observation, not a broad pattern.

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-...

> 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.

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.

SQL is a language. Perhaps you meant a particular implementation like Microsoft SQL Server?

Thank you for being pedantic. Clearly in an article focused on Microsoft, where I specifically call out Microsoft porting SQL to Linux, I meant the language and not the product. I'll be sure to type out "Microsoft SQL Server 2019™" because who would know what I'm talking about otherwise? Oh right, you and everyone else on HN.

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