[Dovecot] Migration questions...

[Stewart Dean]

I'd point out that the big *practical* issue with mbox is the reality of 
big inboxes.  While you can restrict the hoi polloi to something limited 
like a quota of under 60MB (and remember that inbox is one big honking 
file), the powers that be will not allow themselves to be so 
limited...nor will they be particularly good about cleaning up.  I dunno 
how it is with you and your hardware/OS implementation, but there is a 
serious CPU hit when somebody with a 1GB inbox (one big file, remember) 
deletes a message...or gets new mail...or searches their inbox (I call 
this the python swallowing the pig).  The first two will be trivial when 
we switch to maildir.
OTOH, boy is it quick to do a backup with mbox.  I dread that part of 
our move from mbox to maildir format.  We will probably go from 2 hours 
to a day in the switch from 3000 inboxes of one file each (mbox)  to 
3000 directories with hundreds or thousands of files in each (maildir).  
Pick your poison

Timo Sirainen wrote:
>
> On May 13, 2009, at 9:57 AM, Richard Hobbs wrote:
>
>> OK... so Dovecot is certainly significantly faster that uw-imapd in both
>> cases, but is dovecot fastest with mbox or maildir? I would assume
>> maildir, but you never know...
>
> It's not that simple to answer. With mbox it's probably faster to read 
> through all mails, because they're in a single file. With Maildir it's 
> faster to delete mails, because it only needs to delete a single file, 
> instead of moving data around in the mbox file. But Maildir has less 
> problems and it's much less likely to get corrupted, so even if mbox 
> performance would be better in some cases I'd recommend Maildir.
-- 
"One must think like a hero to behave like a merely decent human being." 
- May Sarton Stewart Dean, Unix System Admin, Bard College, New York 
12504 sdean at bard.edu voice: 845-758-7475, fax: 845-758-7035