There is an interesting (and quite long) article about SQL Server and disk cache in MS site.

https://support.microsoft.com/en-us/kb/234656

They talk about "enhanced caching controllers" and they say things like the following:

• - SQL Server installations are targeted at systems that provide caching controllers. These controllers disable the on-disk caches and provide stable media caches to satisfy SQL Server I/O requirements.
• - Your SQL Server installation depends on the controller's ability to disable the on-disk cache and to provide a stable I/O cache.
• - Note: If you have any question about the caching status of your disk drive, contact the manufacturer and obtain the appropriate utility or jumper settings to disable write caching operations.

You even can see a list of different HD drive types (IDE, ATA, SATA, SCSI) with instructions to disable disk cache. In any of them you will see the following phrase:

• - Disk caching should be disabled in order to use the drive with SQL Server.

 

Hi Eduardo,

Can you please give links to these articles?

Regards,
Alexey Kovyazin
IBSurgeon

I searched in Google and found that, for instance, MS suggests not to install SQL Server in a domain controller, but for security reasons. In some articles, MS even recommends to disable disk write cache when installing SQL Server.

I searched information about others RDBMS and generally they recommend to disable disk write cache to ensure database integrity. This seems reasonably. That´s why I am surprised about the difference in performance.

Regards

Eduardo

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