On Mon, 13 May 2002 10:46:09 +0200 (CEST), Andreas Aardal Hanssen wrote: > Are you saying that the standard UNIX mailbox format is safer and more > consistent than, say for instance, Bernstein's Maildir format? If so, > please explain because I don't immediately see this.
The main problem with maildir (leaving aside disk and inode usage issues) is that it is harder to use UNIX tools with it and that it is not designed to handle IMAP metadata. Also, you must have a filesystem (such as on Linux) which has fast open() calls or you will kill performance. However, it is a myth that the steps taken by maildir are the only ways to accomplish safe mailbox handling. A better description is that they are the ways to accomplish safe mailbox handling over NFS in a one file/message type format and only file operations to accomplish locking. Maildir does use locking; it locks by means of file operations and the roles of those three directories. Most problems with safe handling of the traditional UNIX mailbox format are due to people not understanding locking, and choosing to disable code that causes warning messages rather than fixing the underlying circumstances which cause it. A traditional UNIX mailbox guarded by properly implemented dot-lock locking is quite safe, even on NFS. It isn't fast (that wasn't what we were discussing), but it is safe. In certain other formats (e.g. my mbx format, and the Cyrus server format), there is simply a flat prohibition on the use of NFS.
