Cluster size 8 or 16 please advice (XP only)

Discussion in 'Acronis Disk Director Suite' started by admsupport, Jan 28, 2009.

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  1. admsupport

    admsupport Registered Member

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    It is indirectly related to this thread (very annoying this vista!) and this one

    On a NTFS Disk (XP only - unless to follow the first link before making any changes):
    80 GB: 2 partitions: C:\system (20 G) and D:\Documents (60G)
    What's would be the best cluster size to balance a small MTF and a waste of space 8 or 16?

    I have already changed the default 4 cluster to 8 from Windows directly using DD and without any problem (I was thinking about going for 16, even on the system partition but did not do it). Reading the posts from K0lo, see both links above, I am now re-thinking about this setting.

    NB: on a 500 GB USB-HD, changing the cluster from 4 to 32 was a hug kick in the defrag time and disk access, but the wasted space was also proportional. Since I have various documents (not only large files) I reverted to 16 cluster. what about a small disk with 2 partions 20 g and 60 g?
     
    Last edited: Jan 28, 2009
  2. K0LO

    K0LO Registered Member

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    admsupport:

    Disk Director will analyze your disk and display a graphic showing the wasted space for various cluster sizes. Right-click on a partition and choose "Change Cluster Size" to see:

    clusters.PNG

    As you can see, for this disk (which stores huge .tib files), the wasted space is virtually the same for all choices of cluster size. The optimum cluster size, in terms of minimizing wasted space, is not the same as the optimum in terms of speed. Larger cluster sizes result in better disk performance but may result in more wasted space. You need to analyze your own disk to make that decision.

    Personally, with hard disk sizes being so large today I don't think wasted space is an issue.

    As you can tell from the threads referenced, I use 4k on the boot partition and 16k on the OS partition. 16k was only chosen because Microsoft recommends that for disks with Volume Shadow Copy Service (VSS) since VSS works in units of 16k blocks. 16k clusters supposedly minimize the deletion of shadow copy files when the defragmenter runs. For speed, maybe a larger cluster size will work better - I haven't tested it.

    I recently installed Windows 7 on my laptop and made the same choices there as on my Vista machines - 4k for a boot partition and 16k for the Win7 partition.
     
    Last edited: Jan 29, 2009
  3. admsupport

    admsupport Registered Member

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    Only two questions:

    1. I don't understand the values under "allowable partition size" in the red rectangle. The max value is that the size of the partition, what's on the left.
    2009-01-30 10-05-13.png

    2. Do you have any idea if the thread I referred to, in another of my post is accurate:

    There is so much noise at the end of his post, I wonder if it is accurate? Have you tried 16 K cluster on a XP SP2 system partition? The MS JP support desk is (particularly) reluctant to answer any technical question outside the MS specs, i.e. 4 k cluster.
     
  4. K0LO

    K0LO Registered Member

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    1. That's the smallest size you can resize your existing partition to.
    2. I don't know - never tried it.
     
  5. admsupport

    admsupport Registered Member

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    Thank you

    I will call MS beginning of next week. Shall I post their answer on this thread (any interest?)
     
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