High performance tape systems such as the StorageTek Redwood and IBM 9490 work closer to their designed data transfer rates when larger block sizes are used. SAM-FS 3.1 allows the system administrator to configure the block sizes by media type. Block sizes can be set from 16k bytes to 1024k bytes.

See the defaults.conf(4) and plabel(1M) man pages for details.

This release has a new archiver feature which allows more than one tape drive to be enabled for use on an archive set. The actual number of drives to be used is an administrator defined parameter.

A second performance feature is an improvement in the time for the arfind process to search a filesystem looking for archive candidates. In previous releases, the time for arfind to search the entire filesystem would increase roughly in roughly linear fashion to the size of the number of files. Customer use tends to be of steadily growing filesystems with a relatively small amount of changed files. For this type of usage the new arfind process will run substantially faster, after an initial complete file system search is done. Speed still varies by total file system size and amount of change, but best case improvement is by an order of magnitude.