Re: mbox vs. Maildir (was: Re: [Evolution] expunge speed)

[Alexander Skwar <ASkwar digitalprojects com>]

So sprach »Dan Berger« am 2001-08-20 um 13:40:36 -0700 :
> So, there are several problems with your conclusion - first and

Several?

> What about fragility?  Since mbox is a linear ASCII format - any
> corruption of the file (software has bugs, it happens) has the
> potential to destroy the entire mailbox?

Yes, that's right.  In many years this has never happened to *ME*, so I
disregarded that.  But you are right - Maildir is superior wrt. this.

> What about size?  Since attachments are stored in MIME format - an
> mbox with many large messages becomes very large.  MUA's have to
> either perform sequential IO (slow) or memory map the entire file
> (not scalable).

Size?  Well, according to 'du' the Maildir is bigger than the single
file.  Which GOTTA be wrong.

What do you mean by slow?  Reading the last message of this 5000
message/50 MB file in mutt/elm/pine/Evolution is as fast as reading the
same file from Maildir.  I'm lost here.

> It's certainly true that mbox is handled by more clients, but you
> admitted in your message that delete times are slower than maildir - so
> I don't see how you support the assertation that mbox is "faster."

Well, from my usage pattern I also wrote that I normally only delete
files which are close to the end of the file.  There deleting is quite
fast - 1 second for the last.  This would mean, I could open the mbox,
delete the last file, re-open it 3 times before the Maildir has even
opened once.  So, I hardly notice 1 second delay.  And normally my
mbox'es aren't that huge.  My Maildir's also wouldn't be that huge, btw.

> "fast enough for you" I'd agree with - but "faster" isn't generally
> true.

Hmm, faster in the most cases I use.  Agreed?

> Out of curiosity - when deleting messages from the mbox in your
> testing - did you ensure that all clients were actually re-writing the
> file on delete?  (not just flagging the message)

Yes, of course.

> Maildir has constant time add and delete behavior - mbox is linear (mh

Hmm?  Shouldn't mbox's add time also be constant?  I mean, to add to the
file, doesn't "it" just jump to the end of the file and append the new
content?

> directory - but neither one performs well in the large.  Maildir and

How large?  Really, I'd be interested to know this.  I'd consider 50 MB
pretty darn large for a mail file.

> mh can be tuned by "fixing" the filesystem.  Mbox can't be tuned.

Hmm, you mean Maildir & MH could theoretically be "fixed", right?  But I
see your point.


Alexander Skwar
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