Microsoft KB Archive/112555

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LAN Manager Fault Tolerance Corrupts Data on Boot Mirror

Article ID: 112555

Article Last Modified on 9/30/2003



APPLIES TO

  • Microsoft LAN Manager 2.1 Standard Edition
  • Microsoft LAN Manager 2.1a
  • Microsoft LAN Manager 2.2 Standard Edition



This article was previously published under Q112555

SYMPTOMS

The mirroring process for Microsoft LAN Manager produces corruption on the mirror of the boot volume, most noticeably with large (around 40MB) files. There are various symptoms. After unmirroring a drive, large files and their directories may show evidences of corruption: inability to do a directory on C:\PUBLIC when large files reside there, incorrect data on the screen when you use the Type command to display a text file[ASCII 146]s contents. If the drive is unmirrored using FTSETUP, on reboot, CHKDSK finds a number of corrupt files/directories and removes them from the former mirror.

CAUSE

Some casts of longs to shorts in FTDLL.DLL and FTSETUP.EXE caused sector runs of greater than FFFF length to be copied incorrectly to the duplicate drive during the mirroring process, escpecially when drives containing a lot of data were mirrored.

STATUS

Microsoft has confirmed this to be a problem in LAN Manager versions 2.1, 2.1a and 2.2. 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.


Additional query words: 2.10 2.10a 2.20

Keywords: KB112555