Jim - Pre-fetching for a restoral is something that isn't done.

Where you know ahead of time that a file system may be jeopardized by
scheduled system maintenance, you could perform a full backup of it
so as to have its data fresh and contiguous on TSM server media.

In unpredictable failure situations, your chosen storage pool
architecture comes into play, where recent data is available on in a
higher level, fast-access storage pool in the hierarchy, with older
data having migrated to slower, more economical storage pools below.
The product provides various opportunities to have most-needed data
most readily available for recoveries.

  Richard Sims