Hi Jeff, thanks for replying. I don't know how long a full restore on this particular test machine takes, but I suspect longer than 2 hours. The machine is in a seperate virtual testenvironment with old hardware and I don't have the space to restore the entire database. In another testenvironment, with better h/w, it takes about 1-2 hours.

The filegroups are all read/write. Indeed all read/write filegroups will be restored with the PRIMARY filegroup during piecemeal restores, if the database is in simple recovery mode. But it isn't, it's in full recovery mode.

From BOL:

"Every piecemeal restore starts with an initial restore sequence called the partial-restore sequence. Minimally, the partial-restore sequence restores and recovers the primary filegroup and, under the simple recovery model, all read/write filegroups. "

(http://msdn.microsoft.com/en-us/library/ms177425(v=sql.105).aspx)