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Re: ext3 and chattr +S on postfix spools



On Tue, 2002-02-05 at 15:26, Wietse Venema wrote:
> Erik Smit:
> > On Tue, 2002-02-05 at 14:08, Wietse Venema wrote:
> > > Erik Smit:
> > > > On Tue, 2002-02-05 at 04:20, Wietse Venema wrote:
> > > > > ext3 is unsafe for maildir, and with softupdates, so is ffs.
> > > > > One step forwards, two steps back.
> > > > > 
> > > > > Fortunately, some people still have a choice.
> > > > 
> > > > For the newbies among us (me :) would you mind explaining what exactly
> > > > causes it to be unsafe? As far I know (but like I said, I'm just a noob)
> > > > ext3 is journalling metadata and data so I cannot understand how data
> > > > could be lost.
> > > 
> > > maildir delivery requires that certain file system operations are
> > > atomic and synchronous.
> > > 
> > > [...]
> > >
> > > Translated into ext3 speak that means: the link and unlink operations
> > > are written to the log before the respective system call returns.
> > 
> > Excuse my ignorance, but since it has been written to log and the
> > machine would crash before the systemcall returns wouldn't this mean it
> > would be recovered (by journal replaying) during boot?
> 
> IFF the information is written to the ON DISK log, then the
> recovery is possible.

Wasn't that the whole point to journaling filesystems (and chattr +S)?

Regards,

Erik Smit





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