Chris - Restorals are the weakness of an "incremental forever"
        backup scheme, and as you can imagine has been a
perennial topic of discussion on the List.  Here is a reposting of
some approaches I have accumulated over time.
  Richard Sims, BU

Restoral performance                    - Avoid use of the COMPression option
                                          for backups, as the client will have
                                          to uncompress every file being
                                          restored!
                                        - Use Collocation...to the extent that
                                          you can afford it in Backups.
                                          Collocation by FILespace will optimize
                                          restorals but cost a lot in tapes and
                                          tape mount time.
                                        - ADSMv3 Small File Aggregation helps
                                          speed restorals.
                                        - Do Selective backups periodically to
                                          effect a "full" backup and thus a
                                          complete, contiguous image of the
                                          filespace.
                                        - ADSMv3 "No Query Restore" speeds
                                          restorals by eliminating the
                                          preliminary step of the server having
                                          to send the full repertoire of file
                                          objects it has for the client, and the
                                          need for the client to traverse the
                                          list if it already knows what needs to
                                          be restored.
                                        - Maximize your buffer sizes; but watch
                                          out for performance penalty at certain
                                          TCPBufsize sizes (q.v.).
                                        - Minimize your MOUNTRetention value for
                                          the duration of the restoral so as to
                                          avoid a new tape mount having to wait
                                          for a lingering tape to be dismounted
                                          from that drive.
                                        - Consider disabling sync for that file
                                          system for the duration of the
                                          restoral.  There is also the public
                                          domain 'fastfs' program for Solaris
                                          systems, to speed restorals through
                                          use of delayed I/O.
                                        - Minimize other server activity during
                                          the restoral period.
                                        - Restoral works by reconstructing the
                                          file system directory structure first.
                                          The directories for many operating
                                          systems reside in the ADSM database
                                          itself; but if yours goes to a storage
                                          pool, make the storage pool disk (as
                                          via DIRMc).