NTFS Performance Problem with Many Files

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1
• Microsoft Windows NT Workstation version 3.5
• Microsoft Windows NT Server version 3.5

SYMPTOMS

An NTFS volume containing a very large number of files may exhibit degradation in performance when you create new files.

CAUSE

In an effort to provide consistently good performance, the Windows NT file system (NTFS) reserves a portion of disk space for use by the file system itself. In situations where very little disk space is available, Windows NT may need to release some of this space in order to allocate space for user files. In the vast majority of cases, this algorithm works well. In one specialized case, however, it is possible for the algorithm to actually degrade performance by a significant amount.

The worst case occurs if all of the following conditions are true:

• NTFS is formatted with a smaller cluster factor than the default.
• Less than 1/8th of the total disk space is available.
• The volume has never had more files on it at one time than it has now.

WORKAROUND

To work around this problem, reduce the total number of files on the volume or reformat the volume. To minimize the impact of the problem when a very large number of files is required, attempt to create the smaller files first before most of the disk space is already in use.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 3.5. A fix to this problem is in development, but has not been regression-tested and may be destabilizing in production environments. Microsoft does not recommend implementing this fix at this time. Contact Microsoft Product Support Services for more information on the availability of this fix.