A.4. Server and Remote Logon Installations
Some exporters elect to install Syscob applications on “terminal server” or “application server” systems (or even in the “cloud”). In such environments multiple users execute on the same server, or “farm” of servers, and connect to that server either through terminal clients (X11 or thin-client terminals or X terminals) or from a remote PC. Syscob applications can run in virtually any remote access environment.
Terminal or Application Server Installs
Terminal servers, like Windows Terminal Server [WTS] or Citrix or Novell GroupWise, and application servers (e.g. Novell exteNd or Citrix XenServer) can host Syscob applications if some simple concepts are recognized and used as a basis for the installation.
User Logon Defines a “Virtual PC” [VPC]
When a user logon to the server occurs their “profile” and/or logon or startup scripts must create a virtual environment that looks like a Windows® PC providing either “Win32” or “WoW64” APIs, virtual (or actual) drives identified by letters and named printers.
User has “Admin” Rights for Logon VPC
Within the logon environment a users must possess true administrative privileges and access permissions to their virtual (or actual) drives and “local machine” Registry hive.
User VPC has “Local” & “Server” Drive Letters
Such environments must employ a multi-user, rather that “standalone” single user, topology (i.e. distinct “local” and “server” drive letters). All user logons must access the same “server” content whether in the root directory of a physical or virtual drive letter.
Although it would be acceptable to have all user logons share the same application “local” drive contents most sites using terminal or application servers opt to use the logon “home” drive for the logon as its “local” drive. Of course, this can be a common physical location on the server unless other considerations prevent mapping the same site as the “home” drive for more than one logon.
Remote Desktop and Remote Logon
Any form of “remote logon”, whether via Remote Desktop or or other mechanism, must be based on the same concepts. After logon the user must “see” a VPC as described above.
Virtual Private Network [VPN] Logons
When a VPN is used to connect a Windows® PC to a LAN or server which holds the Syscob application database, or vice versa, then the speed of the VPN connection may be an issue if the application programs, libraries and resources are not resident on the machine where the logon executes. In simple terms, while “executing across a LAN” does not give optimum performance, running across a VPN can be worse (e.g. retrieval of UI graphics, loading libraries or executing a DBMS module over a VPN can be m-u-c-h slower in comparison to when they are on the machine where the user logon exists).
If using a VPN and performance appears to be an issue please contact Syscob Support and explain the topology and concerns. Tools to diagnose and repair poorly configured servers and workstations connected by VPN exist to remedy most VPN speed issues.
When planning to install, or move, Syscob applications into any form of remote logon environment customers are advised that contacting Syscob Support with the plans, before the operation, is the best way to avoid unforeseen difficulties arising during the process.