Partition/Cluster Size/Wasted Space

Discussion in 'Dell' started by Bruce, Sep 9, 2006.

  1. Bruce

    Bruce Guest

    I run Windows XP Home, SP2, NTFS.

    I heard on a radio show (Online with David Lawrence) that when
    partitioning drives, the larger the partition, the larger the clusters,
    therefore the more wasted space. I may have misunderstood, but I did
    google the subject, and what I found (and am able to understand - most
    was very technical) leads me to believe this is correct.

    My understanding is that regardless of how many partitions are made, the
    same capacity will be reported. But, when data is added/stored on the
    drive, a multi-partitioned drive will fill up slower because less space
    is wasted. Also, the larger the file size, the less wasted space.

    Is this true, and to what extent?

    I've got the following IDE drives that I'll be adding to other machines,
    which I plan to format as one partition. I've read about single
    partition vs multi-partition, and the pros and cons of each. I find it
    easier to navigate with fewer logical drives than half the alphabet
    showing up on my computer.

    250GB external USB Seagate (currently formatted FAT32 and hooked to this
    NTFS machine and used as a backup )
    160GB internal Seagate (to be used as a primary)
    160BG internal WD (to be used as a slave)

    For me, space isn't an issue, since my needs are generally low. I don't
    do a lot of mult-media stuff (yet?). Also, storage is cheap, but I was
    curious about this.

    Thanks,
    Bruce
     
    Bruce, Sep 9, 2006
    #1
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  2. Hi!

    > I heard on a radio show (Online with David Lawrence) that when
    > partitioning drives, the larger the partition, the larger the clusters,
    > therefore the more wasted space.


    That is generally correct, and no matter the file system type you use, there
    will always be some waste. Most, if not all, file systems have one "smallest
    unit of storage" that they recognize/define, and the size of this smallest
    unit can change as the total disk or partition size goes up. As an example,
    let's say that a file is 5 kilobytes in size, and the disk is formatted so
    that 4 kilobytes is the smallest unit of storage available. This means that
    the 5KB file is going to take up 8KB of disk space. Even though it is only
    5KB in size, the clusters are laid out in 4KB...so the 5KB file must use two
    of them and leave 3KB of space "unused".

    Modern file systems do a lot to alleviate this issue, but there is still
    some waste.

    As an aside, but on a related note, it is possible with some file systems to
    actually define the minimum cluster size. This is done for performance or
    efficiency reasons. If you plan to store a lot of large files, using larger
    clusters will reduce the overhead encountered each time a cluster must be
    found, prepared for use and finally read or written to. With many small
    files, however, this method would be very wasteful of disk space...so
    smaller clusters are defined in this case. These are slower to access, but
    offer more efficient usage of the storage that is available.

    > My understanding is that regardless of how many partitions are made, the
    > same capacity will be reported.


    Yes, but only in a way. If you have several partitions, they will all be
    smaller than the total size of the drive. After all, the partions must all
    fit on the drive and cannot overlap one another. They can (but do not
    necessarily have to) all add up to the total size of the drive. (It is
    possible, though usually not done, to leave a portion of a drive totally
    unpartitioned.)

    > Is this true, and to what extent?


    Yes, it generally is true. See the beginning paragraph for an example.

    A few big files will waste less space than many small files because there
    will not be a lot of partially filled clusters with the large files. There
    will be a few, but they will appear at the end of the file.

    > I find it
    > easier to navigate with fewer logical drives than half the alphabet
    > showing up on my computer.


    Today the biggest advantage of having separate partitions is just to keep
    things separated. Some people like to maintain a separate partition to store
    their personal data. Their programs live on another partition. Doing things
    this way can provide a little extra protection for data files in the event
    that the operating system or a program fails and does some degree of damage.

    > Also, storage is cheap, but I was curious about this.


    Hope this helps to explain things a little better.

    William
     
    William R. Walsh, Sep 9, 2006
    #2
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  3. Bruce

    Bruce Guest

    "William R. Walsh" <>
    wrote in news:zNEMg.134932$FQ1.53101@attbi_s71:

    > Hi!
    >
    >> I heard on a radio show (Online with David Lawrence) that when
    >> partitioning drives, the larger the partition, the larger the
    >> clusters, therefore the more wasted space.

    >
    > That is generally correct, and no matter the file system type you use,
    > there will always be some waste. Most, if not all, file systems have
    > one "smallest unit of storage" that they recognize/define, and the
    > size of this smallest unit can change as the total disk or partition
    > size goes up. As an example, let's say that a file is 5 kilobytes in
    > size, and the disk is formatted so that 4 kilobytes is the smallest
    > unit of storage available. This means that the 5KB file is going to
    > take up 8KB of disk space. Even though it is only 5KB in size, the
    > clusters are laid out in 4KB...so the 5KB file must use two of them
    > and leave 3KB of space "unused".
    >
    > Modern file systems do a lot to alleviate this issue, but there is
    > still some waste.
    >
    > As an aside, but on a related note, it is possible with some file
    > systems to actually define the minimum cluster size. This is done for
    > performance or efficiency reasons. If you plan to store a lot of large
    > files, using larger clusters will reduce the overhead encountered each
    > time a cluster must be found, prepared for use and finally read or
    > written to. With many small files, however, this method would be very
    > wasteful of disk space...so smaller clusters are defined in this case.
    > These are slower to access, but offer more efficient usage of the
    > storage that is available.
    >
    >> My understanding is that regardless of how many partitions are made,
    >> the same capacity will be reported.

    >
    > Yes, but only in a way. If you have several partitions, they will all
    > be smaller than the total size of the drive. After all, the partions
    > must all fit on the drive and cannot overlap one another. They can
    > (but do not necessarily have to) all add up to the total size of the
    > drive. (It is possible, though usually not done, to leave a portion of
    > a drive totally unpartitioned.)
    >
    >> Is this true, and to what extent?

    >
    > Yes, it generally is true. See the beginning paragraph for an example.
    >
    > A few big files will waste less space than many small files because
    > there will not be a lot of partially filled clusters with the large
    > files. There will be a few, but they will appear at the end of the
    > file.
    >
    >> I find it
    >> easier to navigate with fewer logical drives than half the alphabet
    >> showing up on my computer.

    >
    > Today the biggest advantage of having separate partitions is just to
    > keep things separated. Some people like to maintain a separate
    > partition to store their personal data. Their programs live on another
    > partition. Doing things this way can provide a little extra protection
    > for data files in the event that the operating system or a program
    > fails and does some degree of damage.
    >
    >> Also, storage is cheap, but I was curious about this.

    >
    > Hope this helps to explain things a little better.
    >
    > William
    >
    >
    >


    Thanks very much, you've reinforced my intuition and filled in some gaps
    for me. Very nice reply which I'll archive.

    Bruce
     
    Bruce, Sep 9, 2006
    #3
  4. Bruce

    Guest

    Bruce wrote:
    > I run Windows XP Home, SP2, NTFS.
    >
    > I heard on a radio show (Online with David Lawrence) that when
    > partitioning drives, the larger the partition, the larger the clusters,
    > therefore the more wasted space.


    Yes, that's true. The term is called slack space. Files must be
    allocated at least 1 cluster, and files cannot share clusters (It's
    called cross-linking, and it's bad). So a small text file containing
    "Hello World.", even though it's only 12 bytes long will still take up
    512 bytes, Or however many bytes the cluster size happens to be.
    Leaving 500 bytes of slack.

    Don't worry overmuch about it, you have LOTS of room. Since most files
    will take up multiple clusters anyway. Very few people bother with
    cluster size. Radio show hosts should avoid scaring people into
    reformatting their drives just to "recover" the couple megabytes total
    a smaller cluster size would save. :)

    For example. My "Program Files" Folder is 2,471,894,576 Bytes, but is
    taking up 2,489,942,016 Bytes. Leaving 18,047,440 Bytes in "slack" This
    works to be 17.21MB out of 2.31GB, or 0.73% slack.


    I may have misunderstood, but I did
    > google the subject, and what I found (and am able to understand - most
    > was very technical) leads me to believe this is correct.
    >
    > My understanding is that regardless of how many partitions are made, the
    > same capacity will be reported. But, when data is added/stored on the
    > drive, a multi-partitioned drive will fill up slower because less space
    > is wasted. Also, the larger the file size, the less wasted space.
    >
    > Is this true, and to what extent?


    Larger average file size will take up more clusters. And therefor more
    clusters will be 100% full. Reducing "slack".

    The part about multi-partitioned hard drives filling slower is also
    true, but.... it's a bit weak, the effect would not be enough to
    notice. And, each partition would lose some space to the File
    Allocation Table, or the NTFS equivlent. So the effect would be
    partially cancelled out.

    >
    > I've got the following IDE drives that I'll be adding to other machines,
    > which I plan to format as one partition. I've read about single
    > partition vs multi-partition, and the pros and cons of each. I find it
    > easier to navigate with fewer logical drives than half the alphabet
    > showing up on my computer.
    >
    > 250GB external USB Seagate (currently formatted FAT32 and hooked to this
    > NTFS machine and used as a backup )
    > 160GB internal Seagate (to be used as a primary)
    > 160BG internal WD (to be used as a slave)
    >
    > For me, space isn't an issue, since my needs are generally low. I don't
    > do a lot of mult-media stuff (yet?). Also, storage is cheap, but I was
    > curious about this.
    >
    > Thanks,
    > Bruce
     
    , Sep 11, 2006
    #4
  5. Bruce wrote:
    > I run Windows XP Home, SP2, NTFS.
    >
    > I heard on a radio show (Online with David Lawrence) that when
    > partitioning drives, the larger the partition, the larger the clusters,
    > therefore the more wasted space. I may have misunderstood, but I did
    > google the subject, and what I found (and am able to understand - most
    > was very technical) leads me to believe this is correct.


    What the radio guy described is true for the FAT2 file system, the
    bigger the HDD/partition the bigger the clusters. It's forced by the
    FAT2 design. NTFS is another animal entirely in that you can define your
    300GB HDD using 4K clusters, resulting in much less slack space.

    Thanks to whoever posted re: using larger clusters for HDDs with larger
    files - I have 2 unpartitioned 300GB HDDs devoted to video and I think
    I'll convert from 4K to 8K clusters, thinking that along with reduced
    access time in general it might result in less overhead when capturing,
    thus less chance of dropping a frame.

    This is consistently a great NG. :)
     
    Sparky Spartacus, Sep 11, 2006
    #5
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