HanShi (6/6/2014)
I was in doubt, because I found it difficult to get the intention of the question (perhaps because I'm not native English speaking). Did I need to take the question literally ("database needs to go offline when starting a restore") or do I need to take the question in general ("database needs to be offline during all the restore sequenses).So I chose the wrong answer....
I had the same question as you, HanShi, and I am a native English speaker. 🙂
I had to do some reading and was able to find the topic in BOL. The 5th paragraph, 3rd sentence reads "During the piecemeal-restore sequence, the whole database must go offline."
See the topic, "Online piecemeal restore scenario". I believe the process is: Entire database goes offline, Primary filegroup is restored, Primary filegroup comes back online, Subsequent filegroups can be brought online one at a time.
I have not performed a piecemeal restore, so those more familiar - please make the necessary annotations!;-)