What specifically happens on the DISK when you create a new .ndf file?

  • Is the new file created by just some place holder changes to the disk?

    Or

    Is the file actually "filled" with zeros or something to begin it's life?

    I don't have the tools/knowledge needed to "look" at what that does on the disk.

    The reason I'm asking (for your good-human-curiosity): we've got a DR process that is watching the disk for any changed sectors and then copies them to the DR machine over a 100Mbps pipe.

    This isn't a problem when you create the basic 2MB file - but we're wanting to regularly pre-allocate 100GB files.

    Placeholder changes would only effect a small number of disk sectors and be sent to the DR site quickly. 100GB of zeroes would mean that the entire 100GB would need to flow over to the DR site in a rush. This would swamp the 100Mbps connection and keep other syncs from happening.

    I'm not able to find any info re: what actually happens on the disk when new database files are created.

    Anyone know?

  • It can be configured either way.

    http://msdn.microsoft.com/en-us/library/ms175935.aspx

    Regards,

    Jason P. Burnett
    Senior DBA

  • I've hot-linked the article.

    I don't know how your system works, but the server does make an entry here that you have a 100GB file in the disk system. If that doesn't swamp your pipe, you should be OK with Instant File Initialization.

  • Instant Initialization = Bacon saved

    Thanks. Don't know why that basic info did come up in my morning o' Google.

    Kudos!

    -Jim

  • Thanks for fixing the link Steve. I am not sure what I did wrong there. 🙂

    Regards,

    Jason P. Burnett
    Senior DBA

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