Reflective Storage with SAN, nAS, HSM > How it works

Share Configuration
During the configuration process, the architecture for the RSA is arranged and the following parameters are defined:
  • Which clients are permitted to access the Workflow Engine Share?
  • Which data types can be written?
  • Which network protocols must be enabled?
Reflective Storage Architecture
In its clearinghouse role the Workflow Engine directs all subsequent file operations to and from all member servers.

Up to four external storage resources, including storage attached network [SAN], network attached storage (NAS) and hierarchical storage management [HSM], can be added to the RSA as distributed storage systems. Each is integrated into the RSA using one of the following rules:
  • Receives all new files written into a specific folder structure, such as \cardio
  • Receives all new files with a specific file extension. such as .dcm
  • Receives all new files, a process commonly referred to as Fan Out
The SilverBack Workflow Engine controls all commands, including file open, file close and related commands. This step ensures that the system resources are available to suit the client's needs. All file activity is automatic and does not require administrative support.
New Files
When a new file is written and closed, the Workflow Engine locks the file and initiates one or more copy processes to distribute the file to all resources defined in the RSA. After each copy, the Workflow Engine database is updated to reflect the new distributed status of the file.
High Water
When a new file is added and Workflow Engine Share increases above the "high water threshold", the Workflow Engine begins to remove the oldest secured content. This process continues until the data level drops below the "Iow water level."
File Requests
Files residing on the Workflow Engine Share are always available and regarded as the highest priority level.

Files that have been removed during a previous high water activity must be retrieved from an external storage resource before they can be released for a client's request. These files are copied from the next highest priority resource on the reflective storage architecture.

Every file that's returned to the Workflow Engine Share maintains its highest priority level until the file's last access date forces its removal during high water activities.