Microsoft responds

By Brian Livingston  |  Posted 2003-12-16 Print this article Print

According to article 321733 in Microsofts online Knowledge Base, writing a file to a server across a network can generate this error message: "Windows was unable to save all the data for the file x. The data has been lost." The article says this has been confirmed as a problem with Windows 2000 Server and Windows XP Pro and Home clients.

Another Knowledge Base article, 293842, says that data loss can occur "under extreme file system stress" but that this was corrected in Windows 2000 Service Pack 3 (released Aug. 1, 2002).

A Microsoft spokeswoman had this to say: "We did work to resolve the issue fully with Service Pack 4 for Windows 2000 on the server and Service Pack 1 and the available hot fix identified in KB 321733 applied to Windows XP. Microsofts testing shows that when the SP1 and hot fix are applied to these [XP] machines, that the issue is resolved. Again, we will be working with this customer directly to help resolve their specific issue."

Tangent product specialist Dan Michalski, who conducted much of his companys original testing, disputes the idea that SP3 or SP4 for Windows 2000 eliminates the data loss. Michalski said hes seen the error on SP4 simply by writing data files from XP with Dlaytest.exe while refreshing a view of the files in Windows Explorer every few seconds. "Were talking about a single server thats completely dedicated to this test and one workstation," he said. "I wouldnt call that extreme stress." This finding is supported by a similar report from insurance software company Applied Systems.

Tangent and Applied Systems indicate in their reports that disabling SMB signing ends the data errors. If your files are still experiencing data loss after applying the service packs and hot fixes mentioned earlier, you can turn off signing using Group Policy and a setting described in article 321733.

The big question for Microsoft is why it imposes delayed writes on server disks at all. An enterprises priority is to get transactional data committed—without fail. Delayed writes, an old disk-cache trick, are a luxury that should be trumped by reliability. Any transient gain isnt worth your pain.

Brian Livingston is editor of BriansBuzz. com. His column appears every other week in eWEEK. To send tips, visit www. Send your comments to


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