According to BOL we know
"On a 32-bit system, database mirroring can support a maximum of about 10 databases per server instance because of the numbers of worker threads that are consumed by each database mirroring session."
My question is: What is maximum number of mirrored DB we can deploy on 64-bit system per one sql instance?
It depends. Do you have a 64-CPU box with 1 TB of RAM or a 4 CPU box with 4 GB? The variety of 64-bit hardware available makes specific guidance difficult.
You will need to test your configuration appropriately regardless.
|||Peter thanks for you answer.
We have got the next configuration :
HP Superdome (1 cell) 4 CPU?(Dual core Itanium 2 1.6GHz, 24 MB Cache),?32GB.
|||In the case of multiple databases, I use a different tack to overcome the problem. If I find any database failed over, I run SQL commands to fail them all over. "ALTER DATABASE [dbname] SET PARTNER FAILOVER" you must proceed the command with "USE [master]". It works in my case as i am running web code against multiple databases at any given point in time, so I have to have them all failover at the same time anyways. The statement to return the state of each database is "SELECT * from sys.database_mirroring WHERE mirroring_guid IS NOT NULL" I read the values programatically and run the appropriate failover statements depending on the values returned.
|||This was extremely useful, I copied it verbatim into a scheduled task that runs every minute and checks this, because we've had the same issue where only some but not all databases fail over. There should be an SQL Server feature to make multiple databases "atomic" for the purpose of failover.
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