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

Timo Sirainen tss at iki.fi
Sat Jul 17 00:31:20 EEST 2010

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.

> 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

> 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 :)

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