Storage fundamentals: misaligned blocks

All Windows versions before Windows Server 2008 may have misaligned windows blocks when provisioning storage.

Intel´s MBR writes 63 sectors at the beginning of the disk. Let´s say the LUN has been formated with NTFS 4 KB blocks. The last and the first 4 KB (ntfs) block of each block on the LUN (for example 64 KB blocks) will cause disk crossing.

This means for reading/writing to disk 4 KB block two disk reads on the storage are needed and this has an performance impact!
note: this problem may also occur on other operating systems

Use diskpart to align the blocks correctly starting at 1024:

list disk
select disk x
                           // select the appropiate disk
create primary align=1024

    Article Details:

    FileID : 37
    Keywords : storage;fundamentals;misaligned blocks;windows 2003;block;diskpart;1024
    Authored by : davidr
    Views : 4607
    Submit Date : 2012-03-12 15:39:55

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