November 2008 - Posts

How many mirrored databases can I have on a server?

By Robert Davis in SQL Server Soldier :: News from the frontlines of the database wars 11-18-2008 9:20 AM | Categories: Filed under: Tips & Tricks, Database Mirroring

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How many mirrrored databases can I have on a server?

10 mirrored databases per server is the recommendation for a 32 bit computer WITH 4 processors or less. 64 bit computers have twice as many threads which means, in theory, that you can have twice as many mirrored databases. Also more processors = more threads = more mirrored databases. I interpolated the recommendations out from the base recommendation to other system profiles as follows:

	32-bit		64-bit
Number of CPUs	Threads	Mirrored Databases	Threads	Mirrored Databases
<= 4 processors	256	10	512	20
8 processors	288	11	576	22
16 processors	352	13	704	27
32 processors	480	18	960	37

Others are correct to point out that this is a recommendation, not a hard limit. What your server can actually handle depends on the architecture as well as the amount of other traffic being handled by the server.

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How many mirrored databases can I have on a server?

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