When a DICOM client requests an image from a specific WFM, the image is searched for according to criteria defined in a preconfigured rules table. If the image is online, it is sent immediately to the client. If the image is stored offline, the WFM passes the request to the LTSMs.
When the LTSMs receives a Fetch request for an image or a study, it first looks for the image/study in the LTSMs cache. If it is not found there, the Fetch request is forwarded to the NetBackup server. The NetBackup server locates the image and moves it from the long term storage media to the LTSMs cache. If the requested media does not reside in the library, a request to insert the media into the library is displayed.
When the request is fulfilled, the DICOM engine in the LTSMs is notified, and the image is moved directly to the original DICOM user and to the WFM. The images fetched to the LTSMs buffer are cleaned automatically by the LTSMs Auto Delete process at the scheduled time interval.