Re: mbox vs. Maildir (was: Re: [Evolution] expunge speed)
- From: Dan Berger <dberger ix netcom com>
- To: Alexander Skwar <ASkwar digitalprojects com>
- Cc: evolution ximian com
- Subject: Re: mbox vs. Maildir (was: Re: [Evolution] expunge speed)
- Date: 20 Aug 2001 20:38:18 -0700
On 21 Aug 2001 00:19:39 +0200, Alexander Skwar wrote:
Size? Well, according to 'du' the Maildir is bigger than the single
file. Which GOTTA be wrong.
no - it's almost certainly right. remember that disks are not allocated
bit-by-bit - they're allocated in blocks/clusters. So small files
actually waste space on disk in a "normal" file system. Again, this is
something that more advanced file systems can be tuned to accommodate.
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
Yes, for a single thread of delivery - but when you have multiple
writers they line up behind a single mutex - hence, linear behavior.
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.
It's not. In a past life I worked on the email infrastructure for an
online service with several million members. Our test cases were
looking at sized ranging from a few hundred k to 100Meg. Maildir starts
to choke (again, in the multiple delivery case) very early - around 300k
if memory serves (this work was done a number of years ago - the details
are getting fuzzy). Maildir scaled nicely once we tuned the underlying
filesystem - we were able to push the bottleneck right down to the disc
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.
see above - there's nothing theoretical about it.
Anyway - I think we've effectively beat the corpse into the ground - if
you've got more questions, feel free to send them to me off-line.
Dan Berger [dberger ix netcom com]
Nolite te bastardes carborundorum
"We are what we repeatedly do. Excellence, then, is not an act,
but a habit."
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