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Advantage Knowledgebase Item




Ref No:
050422-1718
Last Modified:
Wednesday, January 28, 2009
Product:
Advantage Database Server for NT
Category:
Compatibility
Title:
Can ADS Access Data on a DFS (Distributed File System)?
Problem Description:
Advantage requires a server-side alias to be used when the data resides on a DFS. A server-side alias is also needed if the data resides on a NAS (Network Attached Storage).

Without using a server side alias you may receive 7008 or 5004 errors.
Solution:
A server-side alias has to be used to make a Remote connection to the DFS data. Note that if a server-side alias is used in the connection path, LOCAL server will not work because the alias on the server is being used to resolve the path and the local client is not able to resolve the path with the alias in it.

For information on setting up a server-side alias, refer to the help file topic "Server-Side Aliases." Below is an excerpt from the help file on the configuration:


Configuration

Server-side aliases must be placed in a file called adsserver.ini. This file does not exist by default. Create the file using any text editor. The Advantage server uses the error log path configuration value to locate the adsserver.ini file (the default value is c:\).

An example adsserver.ini file with three aliases:

[ServerAliases]
order_db=c:\data\orders
bikes=\\server1\shared_drive\data
flights_db=c:\data

The server-side aliases are in an ini section called [ServerAliases]. Each entry includes the alias name, followed by an equal sign, followed by the path to use when replacing the alias name.

The alias path can be a path including a local drive letter or it can be a Universal Naming Convention (UNC) path. Mapped network drive letters are not supported, and should not be used.

Server-side aliases are cached, but changes made to the adsserver.ini file will be automatically detected by the Advantage Database Server. You do not need to restart Advantage to reflect alias changes. If the adsserver.ini file is updated, there may be a lag of up to 10 seconds before the new alias changes are recognized.

Note: Server-side aliases must always be used in conjunction with the "Ignore Rights" setting of your Advantage client. See the Database Security topic for details. Failure to do so will result in file existence checks, which will use the server-side alias from the client and fail, resulting in AE_FILE_NOT_FOUND (5004) errors.
<End>

If their connection path is pointing directly to the DFS share then only LOCAL server will work (this is the case because the local client is able to resolve the DFS path and pull the data over to be used with LOCAL server).

Also if the data for the DFS is on a server that isn't running the ADS service then the Advantage service has to be logged in using an account that has access to the data (Local System Account will not work - which is the account ADS uses by default).

When making a data dictionary connection to a DFS using an alias (Remote) in ARC the tables will be listed because it's using metatdata in the dictionary file to locate the tables, however a free table connection will not list any tables.

When making a free table connection to the DFS using the alias (Remote) in ARC then the tables will not be listed because the local client isn't able to resolve the path with the alias name in it.
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