Re: Status of fsync() wrt mail servers

[Chris Mason <mason@suse.com>]

On Wed, 2003-09-10 at 06:51, Bennett Todd wrote:
> 2003-09-10T01:29:53 lists@unbeatenpath.net:
> > I'm in the process of researching OSes and filesystems for a new mail
> > system.  I'm hoping to use linux+reiserfs+postfix, and I'm wondering
> > where reiserfs stands wrt to fsync().  Does reiserfs provide a mechanism
> > to have truly synchronous writes with a single fsync() call?  Thanks
> 
> I'm not really fond of the phrase "truly synchronous writes"; it can
> be read different ways by different people.
> 
> What postfix demands (if you wish to adhere strictly to some
> peoples' interpretations of RFCs) is that when fsync returns, the
> filesystem guarantees that even if there's a crash an instant after,
> the file, data as well as metadata, will be intact when the machine
> comes up again. This is in support of a desire to positively commit
> to the sender that the receiving MTA has accepted receipt for a
> message.

This is what reiserfs does, the metadata is on disk after an fsync,
including any renames.

-chris