Opens a file with SQL Server FILE_FLAG_WRITETHROUGH, which appears compelled to write on physical disk. In SQL Server - this is called 'forced unit access (FUA)'; A white paper can be found in this discussion, many scientists respect it and it can explain the slow performance of an ITL process which I am developing on an IBM Shark server.
On Windows Server 2003, I can select an 'Enable Advanced Display' dialog on Disk Manager, I can get an indirect and undocumented document which means that it overrides the overtonation behavior.
Does anyone know whether this is the case or what does this option really do?
This is not the case. SQL Server always has write-enabled enabled on files that are open. This ensures that no write is buffer in the local Windows disk cache. Anything on that disk controller (RAID controller, etc.) or even more will have its own cache (hopefully battery supported and mirror) and even if files are opened under the OS, there will be a separate cash policy. Never write-back on such a cache that does not backup the battery. If you lose power while typing, then your database will get corrupted.
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