[Dovecot] Questions about dbox (sdbox?), mdbox

Brandon Lamb brandonlamb at gmail.com
Sat Jul 17 02:07:45 EEST 2010

On Fri, Jul 16, 2010 at 2:31 PM, Timo Sirainen <tss at iki.fi> wrote:
> On 16.7.2010, at 22.19, Brandon Lamb wrote:
>> My question is basically whether the dbox format is ready for
>> production environment, is sdbox or mdbox more stable/ready than the
>> other or does it matter? What are people's experience/review with
>> running this format (and if you reply can you tell me which one you're
>> using).
> sdbox is really simple. mdbox is more complex. A few people have used sdbox with v1.x, but it's more or less rewritten with v2.0. With v2.0 I'm not aware of any sdbox installations, but there is at least one somewhat large mdbox installation. They've had some problems, but I think those are mostly gone now.

Any recommendation of one over the other? I came across a 2009 mailing
list entry where you showed some benchmark tests that had mdbox as the
fastest. Without any experience yet, my only possible hangup is being
able to restore individual (lost, whatever other reason) mails for
customers. Doesnt really happen but being able to restore individual
versus their whole mailbox is nice, but it happens so rarely it may be
a non issue.

>> Is there any docs/wiki page for migrating from maildir -> dbox?
> dsync migrates between any two mailbox formats and does it as perfectly as it can. http://wiki2.dovecot.org/Tools/Dsync

Awesome, I'll go do some reading and mess with that

>> I have ~450gigs / 14k pop accounts I would have to migrate. Oh thats
>> another question, I have seen "hybrid" throw around, can I take this
>> to mean dbox/mdbox/both support both formats, maybe only new mail goes
>> into the dbox stuff? And if so (or even if not) is there any way to
>> actually convert from maildir to dbox?
> v1.x had some kind of a maildir/dbox hybrid.. until I realized it was just a bad idea. You can have per-user mail location defined in userdb though, so you can convert users a few at a time.
>> Another question, if there is such a conversion tool, does it break
>> UIDLs and require pop3 clients to redownload messages?
> dsync is awesome and preserves everything. But test it anyway just in case. I'd anyway recommend setting pop3_save_uidl=yes and sometimes after that (when you think everyone's logged in at least once) switching to pop3_uidl_format=%g while still running maildir. With Maildir the new UIDLs are then the filenames and with dbox the UIDLs will be message GUIDs. Those are much more permanent than anything based on IMAP UIDs. Not a requirement, but still :)

Cool, if anything I could just have a script login to every users
account and logout and that would do the same thing right? Or does it
have to perform some kind of list or other action?

Any main/major/big reasons to try to go with mdbox over sdbox? sdbox
being really simple = less prone to typos and other bad things

Oh, what about if i migrate to sdbox, then decide to go with mdbox,
will I want to know for sure ahead of time? Granted I guess thats kind
of an obvious yes, but any big gotchas to know about if I did?

Oh yea and dovecot kicks ass btw =P

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