INF: Support for Network Database Files

ID: Q196904

The information in this article applies to:

Microsoft SQL Server version 7.0

SUMMARY

Network database files are generally unsupported under SQL Server 7.0. Attempting to create a database file on a mapped or UNC network location causes error 5105 "Device Activation Error". This is expected behavior. Trace flag 1807 bypasses this and allows network-based database files. This is currently intended for use only for Network Appliance, Inc. storage systems.

MORE INFORMATION

Using network-based database files is generally less safe than a local disk drive, due to inherent uncertainties in network data integrity. For this reason, network-based database files are not generally supported for SQL Server 6.5 or 7.0. This is documented in the following article in the Microsoft Knowledge Base:

Q115043 INF: Network Database Devices Unsupported

As a result of discussion with Network Appliance, Inc (whose Web site is http://www.netapp.com/), SQL Server development and support decided to provide limited support for network-based database files on SQL Server 7.0 by means of trace flag 1807. This support is currently limited to Network Appliance, Inc. storage systems only. However, trace flag 1807 will physically make network-based files work if hosted on a Windows NT file server.

Network Appliance storage systems are typically Ethernet-connected intelligent RAID computers. The TCP/IP protocol is used between the database server and the Network Appliance computer. No additional network error correction or recovery protocols are used beyond standard TCP/IP.

The following describes the behavior of network-based database files on SQL Server 6.5 and 7.0, with and without trace flag 1807. Mapped syntax refers to a drive letter associated with a network path by the NET USE command. UNC syntax refers to a direct reference to a network path, such as \\servername\sharename.

In SQL Server 6.5, a DISK INIT statement that attempts to create a device file on a mapped network drive letter will succeed. If it is attempted on a UNC-style network path, it fails with error 5105 "Device Activation Error".

In SQL Server 7.0 without trace flag 1807, if the DISK INIT backward- compatible syntax is used with either mapped or UNC syntax, error 5105 occurs.

In SQL Server 7.0 with trace flag 1807, if the DISK INIT backward- compatible syntax is used with mapped syntax, file creation succeeds when the CREATE DATABASE statement finishes. This is normal behavior when using the backward-compatible DISK INIT syntax. When using DISK INIT with UNC syntax, error 5105 occurs.

In SQL Server 7.0 without trace flag 1807, if a CREATE DATABASE statement is executed with mapped or UNC syntax, error 5105 occurs.

In SQL Server 7.0 with trace flag 1807, a CREATE DATABASE statement done with mapped or UNC syntax succeeds.

Note that while network-based database files are not supported with SQL Server 6.5, they will physically work if you are using mapped syntax. Starting with SQL Server 7.0, this will no longer work. Therefore, if you are improperly using network-based database files on SQL Server 6.5 and then upgrade to SQL Server 7.0, these would no longer work.

The third-party products discussed here are manufactured by vendors independent of Microsoft; we make no warranty, implied or otherwise, regarding these products' performance or reliability.

REFERENCES

For more information about trace flags, see SQL Server Books Online.

Additional query words: network attached storage NAS devices

Keywords :
Version : winnt:7.0
Platform : winnt
Issue type : kbinfo