The restore may fail when you restore a backup that is stored in tapes on a SQL Server 2000 server that is running Windows 2000 datacenter or advanced Server

Article ID: 280793 - View products that this article applies to.

This article was previously published under Q280793

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SYMPTOMS

When you attempt to restore, or view a tape on Windows 2000 Datacenter Server, or Advanced Server, you cannot view the contents of the tape, and the tape is not recognized. This problem occurs when using the Backup program that is included with Windows 2000 as well as the backup feature in SQL Server 2000.

SQL Backup may display the following error message after attempting to read the tape:

Operation on device "%tape device%" exceeded retry count: Restore HEADERONLY is terminating abnormally.

When you use Backup to restore, in Windows 2000, you continue to receive the following message even though you have inserted the correct tape:

Place Media Tape Catalog Title into drive or library unit.

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CAUSE

The tape that is being restored was created while running Windows 2000 without the Physical Address Extensions (PAE) option enabled. PAE is a feature of Windows 2000 Advanced Server, and Datacenter Server that allows memory above 4 gigabytes (GB) to be accessed by Windows.

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RESOLUTION

Create a new entry in the Boot.ini file to start Windows 2000 without the /PAE switch. Restart the server with the new Boot.ini entry, and then restore the tape. Complete your future tape backups while running in PAE mode.

WORKAROUND

IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986

(http://support.microsoft.com/kb/256986/EN-US/ )

Description of the Microsoft Windows Registry

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

A supported workaround currently exists to resolve this issue. You must add the following registry key to all non-PAE systems that will participate in backups, and restores before a backup operation is attempted:

HKEY_LOCAL_MACHINE\CurrentControlSet\Services\Driver Service Key\Parameters\DeviceN

MaximumSGList : REG_DWORD : 0x10 (16 Decimal) [Default is 0x11 or 17]

Driver Service Key is the SCSI driver name, and N is the zero-based SCSI adapter number supported by that driver. If N is not specified, this registry value will apply to all the adapters described by Driver Service Key. MaximumSGList is a value between 0 and 255. Use this adjustment sparingly as scatter/gather lists consume nonpaged memory.

For example, if your backup hardware were attached to an Adaptec controller, the registry entry might look like this:

HKEY_LOCAL_MACHINE\CurrentControlSet\Services\aic78u2\Parameters\Device\MaximumSGList = (REG_DWORD) 0x10

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