Fix for Loss of Data Records or Partial Records Written to Disk

• Microsoft Windows NT Server version 4.0
• Microsoft Windows NT Server Enterprise Edition version 4.0
• Microsoft Internet Information Server version 3.0

SYMPTOMS

Internet Information Server (IIS) 3.0 logging supports periodic flushing of log file data to disk. By default this interval is five minutes, however you can modify this setting by changing the following registry entry:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\InetInfo\
   Parameters\LogFileFlushInterval

In certain circumstances, data may be lost if the buffer is prematurely flushed. Overall, this leads to a loss of data records or partial records written to disk.

CAUSE

This problem occurs if the lock that protects file data in the periodic flush path is not acquired. This problem happens specifically in the case where the log flush size registry value is set to a large buffer size (for example, 32MB instead of the default 64k).

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\InetInfo\
   Parameters\LogFileBatchSize

RESOLUTION

The fix is to acquire the file-data lock and hence protect against premature flushes or loss of log data.

To resolve this problem, obtain the following fix or wait for the next Windows NT service pack.

This fix should have the following time stamp:

   10/21/97  01:25p               130,320 Infocomm.dll (Intel)
   08/08/97  06:55p               222,992 Infocomm.dll (Alpha)

STATUS

Microsoft has confirmed this to be a problem in Internet Information Server version 3.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.