You can now specify the view build directory in Domino R5 with the NOTES.INI parameter VIEW_REBUILD_DIR = "full path of directory or filesystem." This can be a directory in an existing file system, or a dedicated file system for the view builds. It is not a requirement to set this variable. If a view rebuild directory is not specified, the same functionality is available as in Domino R4. In that case, the temporary directory of the operating system will be used.
Examples: VIEW_REBUILD_DIR=f:\tmp\notesindexer
Suggested addition to any R5 server installation config.
For best performance try to specify this directory on as fast a disk as possible and preferably on a seperate unit/controller.