On Tue, 2010-09-21 at 13:56 +0200, Jakob Curdes wrote:
b) file is corrupt (altered by two processes, bad sector, filesystem corruption on file level) - the mbox file can be repaired easily, if you want, by hand.
With mbox data is moved in-place within the file while doing expunge. A crash in the middle of expunge corrupts the mbox file, although no data will actually be lost with the way Dovecot does it (but you may have duplicate mails and one of the mails could be split into two parts inside the file). A power loss during expunge could be worse and maybe lose data, depending on OS/filesystem.
With maildir a crash will never lose or corrupt anything. A power loss also won't corrupt anything, only (maybe) lose some changes. With filesystem corruption anything can happen of course..