sector alignment- single disk, multiple partitions...

  • We have a SQL Server that's being used as a "standby server". Against my recommendations, the hardware configuration is one big disk (to the OS- actually two disks, striped raid 1). the Best Practice Analyzer came back and said that the starting offset is wrong for all 3 partitions on the disk. (OS, DATA, and Support)... again not my idea.

    The OS admin says since there is only one disk "there is no offset to reset"... I thought that he could still set the starting offset to be a multiple of 64 so SQL Server would do I/O more efficiently. Is this just an admin trying not to have to reinstall the OS?

  • You cannot change the offset on a disk with the built in tools in Windows without reformatting it, but perhaps there are third party tools, like Partition Magic for example, that can do it without reformatting.

  • totally understand that- so the right thing to do is reformat the disk and properly align it?

  • Yes, but you only have to fix the partitions where your databases exists, not the partition where the OS is installed.

    Use the diskpart (link) utility that comes with Windows.

    FYI, in Windows 2008 (and newer) partitions are automatically aligned.

  • yep- that was my exact understanding. OS admin was trying to basically say "it can't be done" because there is only one disk... I think he just didnt want to reinstall the OS.

  • There is no need to reinstall the OS unless you have one partition with everything on it.

    If the data and tranlog files are on a different partition than the OS, you'll only need to align this partition.

  • Deleted - double post.

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