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From "Steve Short" <ssh...@postx.com>
Subject RE: IMAP Development Pointers
Date Thu, 04 Sep 2003 16:18:45 GMT
Jason,

Some links you might find useful:


> -----Original Message-----
> From: Jason Webb [mailto:jw@inovem.com] 
> Sent: Thursday, September 04, 2003 9:07 AM
> To: 'James Developers List'
> Subject: RE: IMAP Development Pointers
> 
> 
> I shall have a think then (and set about doing it)
> DJB's site has a good explanation on how maildir works 
> http://qmail.plig.org/man/man5/maildir.html
> 
> -- Jason 
> 
> 
> > -----Original Message-----
> > From: Edward Flick [mailto:eddy@cdf-imaging.com]
> > Sent: 04 September 2003 15:24
> > To: James Developers List
> > Subject: RE: IMAP Development Pointers
> > 
> > 
> > Yeah, maildirs seem pretty effective as a store.  Thats
> > actually what I was hinting at (with a link file instead of 
> > real links as this is a java program and will be running on 
> > platforms which don't support real links).  I don't buy into 
> > the idea that creating multiple files will cause much more 
> > disk thrashing, as a spool file can be scattered all of over 
> > the drive too. Although, the open/close efficiency issue is 
> > real, BUT I think this can be counteracted with a good 
> > full-text index file.  Also, thanks to the newer journaling 
> > file systems, it would be a lot easier to guarantee that a 
> > message is uncorrupted.  Although, I definetely think the 
> > indexing system should be implemented after a simple maildir 
> > implementation is put into place. Anyways, this would just be 
> > a step to at least get this into something close to a beta 
> > phase.  What do you guys think?
> > 
> > -----Original Message-----
> > From: Jason Webb [mailto:jw@inovem.com]
> > Sent: Thursday, September 04, 2003 3:02 AM
> > To: 'James Developers List'
> > Subject: RE: IMAP Development Pointers
> > 
> > 
> > If there is enough interest or need I will write a
> > maildir-style repository.  This is used by qmail and 
> > Courier-IMAP to great effect and provides folders etc., and 
> > it's safe(ish) over networked file systems. The current 
> > repositories are less than ideal other than for folder based 
> > storage ,particularly the mbox one ;)
> > 
> > -----Original Message-----
> > From: Jim Wright [mailto:jimw@paneris.org]
> > Sent: Wednesday, September 03, 2003 5:40 PM
> > To: James Developers List
> > Subject: Re: IMAP Development Pointers
> > 
> > 
> > Hi Edward,
> > 
> > I have University of Washington IMAP on my Linux machine
> > and use an experimental format mx which is as you describe. 
> To quote 
> > the docs:
> > 
> > . mx    This is an experimental format, and may be removed 
> in a future
> >     release. ...
> > 
> >     [snip]
> > 
> >     mx is somewhat inefficient; the entire directory must be read
> >     and each file stat()'d.  We found it intolerable for a
> >     moderate sized mailbox (2000 messages) and have more or less
> >     abandoned it.
> > 
> >     [snip]
> > 
> > 
> >     There's a general reason why file/message formats are a 
> bad idea.
> >     Just about every filesystem in existance serializes file
> > creation and
> >     deletions because these manipulate the free space map.  
> > This turns out
> >     to be an enormous problem when you start 
> > creating/deleting more than a
> >     few messages per second; you spend all your time 
> thrashing in the
> >     filesystem.
> > 
> >     It is also extremely slow to do a text search through a
> >     file/message format mailbox.  All of those open()s and
> > close()s really
> >     add up to major filesystem thrashing.
> > 
> > I was not completely convinced by this. File system devices
> > are getting faster for a start.
> > 
> > 
> > 
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> > 
> 
> 
> 
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