In the STA data store, media history is retained by volume serial number (VSN or volser). That is, all history for a particular piece of media is tied to its volser. For this reason, it is recommended that you avoid duplicate volume serial numbers (VSNs or volsers) in the tape environment monitored by STA. Volsers should be unique across all monitored libraries. Duplicate volsers will result in co-mingling of data for different pieces of media.
Volsers are considered to be duplicates only if the media with the same volser also have the same domain and type. Domain identifies the media format, and type identifies the version, as illustrated in the following examples:
The same volser used on two different LTO4 cartridges would be considered duplicate, while the same volser on an LTO4 cartridge and an LTO5 or T10000C cartridge would not.
Duplicate volsers may occur for a variety of reasons, such as:
The Duplicate Detected flag appears on the Libraries – Exchanges screen and indicates that the volser involved in the exchange is a duplicate — the media has the same volser as another media of the same domain and type but with a different media serial number (MSN). If you find exchanges with this flag, you should investigate and determine whether to assign a different volser to one of the media, as the data for the two will be co-mingled. See Chapter 6, “Exchanges Screen” for additional information.
Note – Only some drive types and firmware levels report MSNs; therefore, with some drive types, STA may not receive all the information necessary to detect duplicate volsers.
