Incorrect Disk Space reading

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

Hi,
I put in a new NTFS hard drive not to long ago and I
should have about 20gb free but its telling me I only
have 6. Can anyone help me and give me a solution.

Thanks
Cameron
1 answer Last reply
More about incorrect disk space reading
  1. Archived from groups: microsoft.public.windowsxp.hardware (More info?)

    Hi,

    You can troubleshoot the issue by following the detailed instructions in
    the KB article given below:

    http://support.microsoft.com/default.aspx?scid=kb;en-us;315688&Product=winxp

    or

    How to Locate and Correct Disk Space Problems on NTFS Volumes in Windows XP


    SUMMARY

    The NTFS file system supports many volume- and file-level features that may
    cause free disk space to be either misreported or reported as lost. You may
    notice this behavior if an NTFS volume suddenly becomes very full, and you
    cannot find the cause or locate the folders and files that cause the NTFS
    volume to become full. This behavior may occur if a user gains malicious or
    unauthorized access to an NTFS volume on which either very large files or a
    high quantity of small files are secretly copied, and then removes or
    restricts NTFS permissions on these files. This behavior may also occur
    after a system malfunction or a power outage that causes volume corruption
    to occur.

    This article describes how to check NTFS disk space allocation to either
    discover offending files and folders or locate volume corruption. This
    article is intended for users of Windows XP operating systems that support
    advanced storage features and troubleshooting methods.
    MORE INFORMATION
    The disk space allocation of an NTFS volume may be misreported for any of
    the following reasons:
    The cluster size of the NTFS volume is too large for the average-sized
    files that are being stored.
    File attributes or NTFS permissions prevent files or folders from being
    either displayed or accessed when you use either Microsoft Windows Explorer
    or a Windows command prompt.
    The folder path exceed 255 characters.
    Folders or files contain invalid or reserved file names.
    NTFS metafiles (such as the Master File Table [MFT]) have grown and cannot
    be unallocated.
    Files or folders contain alternate data streams.
    NTFS corruption causes Windows to report free space as being in use.
    Other NTFS features cause file-allocation confusion.
    The Cluster Size Is Too Large
    Disk space can be consumed only by files and folders that include internal
    NTFS metafiles, for example the MFT, folder indexes, and so on. Multiples
    of a cluster consume all file space allocation. A cluster is a collection
    of contiguous sectors. The cluster size is determined at the time that the
    volume is formatted and is further determined by the partition size.

    For additional information about clusters, click the article number below
    to view the article in the Microsoft Knowledge Base:
    140365 Default Cluster Size for FAT and NTFS

    After a file is created, it consumes the minimum size of a single cluster
    of disk space, depending on the initial file size. After you add data to a
    file, NTFS increases the file's allocation in multiples of the cluster size.

    To determine the current cluster size and volume statistics, run the
    following command from a command prompt:
    chkdsk d:

    The following text is an example of the output that is displayed if you run
    this command:
    4096543 KB total disk space.
    (This value is the total formatted disk capacity.)

    2906360 KB in 19901 files.
    (This value is the space used by user file data.)

    6344 KB in 1301 indexes.
    (This value is the space used by NTFS indexes.)

    0 KB in bad sectors.
    (This value is the space lost to bad sectors.

    49379 KB in use by the system.
    (This value is includes MFT and other NTFS metafiles.)

    22544 KB occupied by the log file.
    (This value is the NTFS Log file; you use the chkdsk /l:size to adjust this
    value.)

    1134460 KB available on disk.
    (This value is the available FREE disk space.)

    4096 bytes in each allocation unit.
    (This value is the cluster size [4K])

    1024135 total allocation units on disk.
    (This value is the total clusters on disk.)

    283615 allocation units available on disk. (This value is the available
    free clusters.)

    NOTE: Multiply each value that is reported in kilobytes (KB) by 1024 to
    determine the accurate byte size (for example, 2,906,360 x 1024 =
    2,976,112,640 bytes).

    Review this output to determine the default cluster size and how your disk
    space is being used. To see if the cluster is using the optimal cluster
    size, determine the amount of wasted space:
    Double-click My Computer, and then double-click the drive letter (for
    example, D) of the volume that you want to check.
    Click any file or folder, and then click Select All on the Edit menu.
    Right-click any file or folder, and then click Properties.
    Click the General tab, and then review the "Size" and "Size on disk" file
    size values, which calculate the total number of files and folders on the
    entire volume.
    If you are not using NTFS compression for any files or folders that are
    contained on the volume, the difference between the Size value and the Size
    on disk value is the wasted space that occurs because the cluster size is
    larger than necessary. Choose an optimal cluster size so that the Size on
    disk value is as close to the Size value as possible. An excessive
    discrepancy between the Size on disk value and the Size value is an
    indication that the default cluster size is too large for the average file
    size that you are storing on the volume. In this scenario, it is
    recommended that you decrease the cluster size. To do so, back up the
    volume, and then use the format command with the /a switch to specify the
    appropriate allocation size to reformat the volume. For example, run the
    following command for a 2-KB cluster size:
    format D: /a:2048

    Alternatively, you can enable NTFS compression to regain space that is lost
    because of an incorrect cluster size; however, if you do so, you may
    experience a slight decrease in performance.
    File Attributes or NTFS Permissions
    You can use either Windows Explorer or the dir /a /s folder list command to
    report the file and folder statistics for only those files and folders that
    you have permissions to access. Hidden files and protected operating system
    files are always excluded from this report by default. Because some folders
    are excluded, inaccurate file and folder totals and size statistics may be
    displayed by Windows Explorer or dir command outputs. To include these
    types of files in the overall statistics, change Folder Options:
    Double-click My Computer, and then double-click the drive letter of the
    volume that you want to check.
    Click Folder Options on the Tools menu, and then click the View tab.
    Click the Show Hidden Files and Folders check box, and then click to clear
    the Hide protected operating system files check box.
    After you receive the warning message, click Apply.
    After you unhide the files and folders, you can use either Windows Explorer
    or the dir /a /s command to generate the total of all files and folders
    that are contained on the volume to which the user has permissions.

    To determine the folders and files that cannot be accessed:
    From a command prompt, send the output of a dir /a /s to a text file.

    For example, run the following command:
    dir d: /a /s >c:\d-dir.txt

    Start Ntbackup.exe, click Options on the Tools menu, click the Backup Log
    tab, and then click Detailed.
    Click the Backup tab, back up the entire volume that is affected (in this
    example, drive D), and then start the backup procedure.
    After the backup procedure is complete, view the backup report, and then
    compare the folders in the Ntbackup log output with the folders in the
    output that you saved in a text file in step 1.
    The backup procedure accesses all files; therefore, its report may contain
    folders and files that are not seen or counted when you use either Windows
    Explorer or the dir command. If you are looking for large files or folders
    that you cannot use Windows Explorer to access, you may find it easier to
    use the Ntbackup graphical user interface (GUI) to navigate the volume. Use
    the Ntbackup GUI to view the volume without actually backing up the volume.

    After you locate files to which you do not have access, open the file or
    folder's properties in Windows Explorer, click the Security tab, and then
    add or change permissions so that the folder is in included in the dir /a
    /s command output. By default, you do not have access to the System Volume
    Information folder.

    NOTE: You may find that some of the folder or file properties do not
    contain a Security tab, or you may find that you cannot re-assign
    permissions to the affected folders and files. You may receive the
    following error message while you try to access these files:

    D:\folder_name\ is not accessible

    Access is denied

    If you find these types of folders, contact Microsoft Product Support
    Services for additional assistance. To contact Microsoft Product Support
    Services, visit the following Microsoft Web site:
    http://support.microsoft.com/directory/question.asp

    Invalid File Names
    Folders or files that contain invalid or reserved file names may also be
    excluded from file and folder statistics. Folders or files that contain
    leading or trailing spaces are acceptable in NTFS; however, these files are
    not acceptable in the Win32 subsystem. Therefore, neither Windows Explorer
    nor a command prompt can reliably handle files that have leading or
    trailing spaces.

    For additional information, click the article number below to view the
    article in the Microsoft Knowledge Base:
    120716 How to Remove Files with Reserved Names in Windows NT

    Typically, it is not possible to rename or delete files or folders that
    have leading or trailing spaces. If you try to rename or delete these
    folders of files, you may receive one of the following error messages:

    Error renaming file or folder

    Cannot rename file: Cannot read from the source file or disk.
    -or-


    Error deleting file or folder

    Cannot delete file: Cannot read from the source file or disk.
    If you have folders or files that you cannot delete or rename, contact
    Product Support Services at the following Microsoft Web site:
    http://support.microsoft.com/directory/question.asp

    NTFS MFT Expansion
    After you create and format an NTFS volume, NTFS metafiles are created. One
    of these metafiles is called the "Master File Table" (MFT). This file is
    very small when it is created (approximately 16 KB), but it grows as files
    and folders are created on the volume. When a file is created, it is
    entered into the MFT as a file record segment, which is always 1024 bytes
    (1 KB) in size. As files are added to the volume, the MFT grows as
    required. However, when you delete files, the associated file record
    segments are marked as free to be reused, but the total file record
    segments and associated MFT allocation remains the same. This behavior
    explains why you do not regain the space that is used by the MFT after you
    delete a large number of files.

    To determine the exact size of the MFT, use the built-in disk defragmenter
    utility to analyze the volume. View the defragmenter report to obtain
    detailed information about the size and number of fragments in the MFT.

    The following text is an example of the defragmenter report:

    Master File Table (MFT) fragmentation
    Total MFT size = 26,203 KB
    MFT record count = 21,444
    Percent MFT in use = 81 %
    Total MFT fragments = 4


    For a more complete picture of how much space (overhead) is being used by
    the entire NTFS file system, run the chkdsk command, and then view
    resulting output for the following line:
    In use by system.

    Currently, only third-party defragmenter utilities consolidate unused MFT
    file record segment records and reclaim unused MFT allocated space.
    Alternate Data Streams
    NTFS allows files and folders to contain alternate data streams. This
    feature allows multiple data allocations to be associated with a single
    file or folder. Please be aware of the following limitations when you use
    alternate data streams on files and folders:
    Windows Explorer and the dir command do not report the data in alternate
    data streams as part of the file size or volume statistics. Instead, they
    show only the total bytes for the primary data stream.
    The output from the chkdsk command accurately reports space used by a
    user's data files, including alternate data streams.
    Disk quotas accurately track and report all data stream allocations that
    are part of a user's data files.
    Ntbackup records the number of bytes that are backed up in the backup log
    report. However, it does not show which files contain alternate data
    streams, nor does it show accurate file sizes for files that include data
    in alternate streams.
    NTFS File System Corruption
    In very rare circumstances, the NTFS $MFT or $BITMAP metafiles may become
    corrupted and result in lost disk space. To identify and fix this issue,
    run the chkdsk /F command against the volume in question. Toward the end of
    chkdsk process, you receive the following message if the $BITMAP metafile
    needs to be adjusted:
    Correcting errors in the master file table's (MFT) BITMAP attribute. CHKDSK
    discovered free space marked as allocated in the volume bitmap. Windows has
    made corrections to the file system.

    Other NTFS Features That May Cause File Allocation Confusion
    NTFS also supports hard links and reparse points that allow volume mount
    points and folder junctions to be created. These additional NTFS features
    may cause confusion when you try to determine how much space is being
    consumed on a physical volume.

    A hard link is a folder entry for a file regardless of where the actual
    file data exists on that volume. Every file is considered to have at least
    one hard link. On NTFS volumes, each file can have multiple hard links;
    therefore, a single file can be displayed in many folders (or even in the
    same folder with different names). Because all of the links reference the
    same file, programs can open any of the links and modify the file. A file
    is deleted from the file system only after all of the links to it have been
    deleted. After you create a hard link, programs can use the link like any
    other file name. Note that Windows Explorer and a command prompt will show
    all linked files as being the same size, even though they all share the
    same data and do not actually use that amount of disk space.

    Volume mount points and folder junctions allow an empty folder on an NTFS
    volume to point to the root or subfolder on another volume. Windows
    Explorer and the dir /s command follow the reparse point, count any files
    and folders on the destination volume, and then include them in the host
    volume's statistics. This behavior may lead you to believe that more space
    is being used on the host volume than what is actually being used. For
    additional information about junction points, click the article number
    below to view the article in the Microsoft Knowledge Base:
    205524 How to Create and Manipulate NTFS Junction Points

    In summary, use the following methods to correctly determine how the disk
    space is being used on a volume:
    View the output from the chkdsk command.
    Use the Ntbackup GUI or view the backup logs.
    View the disk quotas.
    On the other hand, Windows Explorer and the dir command have some
    limitations and drawbacks when you use them to determine how disk space is
    being used.

    Hope this helps.

    Vijay S

    This posting is provided "AS IS" with no warranties, and confers no rights
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