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..
Since years I am impressed with the stability of our dovecot
installations even under high load situations etc.
So we should probably put it that way:
a) corruption is unlikely with both formats b) if you have (filesystem)
corruption, you need a good backup ...
JC
