A change to Microsoft's tape backup feature makes file
backup tapes created with Windows Server 2003 incompatible with
previous versions of Windows, including Windows XP and Windows
2000.
The problem is caused by a change in the
Windows Server 2003 version of the free ntbackup.exe utility which
comes with Windows operating systems and was first disclosed in the
online security news group NTBugtraq.
The change means that backup tapes formatted
using Windows Server 2003 cannot be used to restore data to Windows
2000 or Windows XP machines, according to Brian Bergin, president
of IT consultants Terabyte Computers.
Microsoft confirmed that the problem affects
Windows 2000 Server and Professional as well as Windows XP, and
experts are questioning whether more incompatibilities will
emerge.
Microsoft said the backup feature in Windows
2000 and Windows XP wrote data to removable media such as magnetic
tape drives in 32K bit blocks, but Windows Server 2003's backup
feature writes data in 64Kbit blocks.
According to Bergin, a manager in Microsoft's
storage services group, said the problem stemmed from an
"oversight" in testing data migration scenarios from Windows 2003
to the Windows 2000 and XP platforms.
Bergin discovered the problem while working on
behalf of his customers, which are mostly small businesses with
between eight and 12 workstations connected to a common file
server.
"Typically, if I have a customer with a server
that goes down, I pull the tape drive and the controller out of the
server and put it in a workstation and restore the files they need.
When the server comes back up, I can copy the files back. You can
go from 2000 to XP and vice versa all day long, but not from
Windows Server 2003," he said.
After discovering the problem in late April,
Bergin reported it to Microsoft technical support. "Their initial
response to me was to tell me to buy third-party backup software,"
he said. That has now changed, he added.
"The problem doesn't affect the integrity or
reliability of the systems, but it delivers a customer experience
that is inconsistent with Microsoft's intended design," Microsoft
said.
Microsoft has created and is testing a fix for
the problem. The company will be issuing the "correction" within
days, after the fix has been tested and documented.
Third-party data backup and recovery software
for Windows Server 2003 is not affected by the problem, Bergin
said.
In the absence of a patch for the problem,
Windows 2003 customers with backup tapes that were formatted on
that platform have to copy the Windows Server 2003 version of
ntbackup.exe to the non-Windows Server 2003 machine.
However, that workaround is not supported by
Microsoft and may be in violation of the company's licensing
agreement, Bergin said.
For organisations that have not yet formatted
their backup tapes, doing the initial format on a Windows 2000 or
Windows XP platform first will ensure that the tapes are formatted
using 32Kbit data blocks and can be used on all the platforms,
Bergin said.
Paul Roberts writes for IDG News
Service