[Dovecot] Questions regarding dbox migration

[Mikkel]

Timo Sirainen skrev:
> On Oct 14, 2009, at 7:03 AM, Mikkel wrote:
> 
>> Now the big question is whether multi-dbox and single-dbox are 
>> compatible formats.
> 
> Kind of, but not practically.
> 
>> If a Maildir->dbox migration is made on a system running dovecot v. 
>> 1.1, would it then be trivial later changing to multi-dbox after 
>> upgrading to 2.0 or is a completely new migration then needed?
>> Would this scenario be much different if the system is upgraded to 
>> version 1.2 before the change to single-dbox?
> 
> Migrating from single-dbox to multi-dbox isn't any easier than maildir 
> -> multi-dbox.


 From your comments it appears like dbox and mdbox are quite different 
in many ways. Is mdbox going to replace dbox completely or are you 
expecting to keep both formats?
My point is: what's going to be the difference between dbox and mbox 
with mdbox_rotate_size set small enough to allow only one mail per file?

> 
> I'm trying to get v2.0.0 out pretty quickly though. v2.0.beta1 should 
> hopefully be out in less than a month. The main problem with it is 
> actually how to make it enough backwards compatible that everyone won't 
> start hating me.

That is great news. I'm looking very much forward to make the shift to 
dbox/mdbox.
A new mail storage format is really, really, really interesting from my 
point of view. CPU and RAM are both very cheap by now but disk I/O 
remains as expensive as always and really is the only limiting factor 
these days and is what's driving up the costs of running any larger mail 
system.
The performance gains you mentioned previously this year would probably 
cut the total datacenter costs in half and that is quite an accomplishment.

How stable do you think dbox and mdbox are at the moment?


Regards, Mikkel