[Dovecot] Questiosn about dbox

[Timo Sirainen]

On 24.1.2011, at 22.45, Javier de Miguel Rodríguez wrote:

> 
>> The intended way to restore stuff is to either restore the entire dbox to a temp directory, or at least all the important parts of it (indexes + the files that contain the wanted mails) and then use something like:
>> 
>> doveadm import sdbox:/tmp/restoredbox "" savedsince 2011-01-01
>> 
> 
>    Thank you for your response, Timo. That was the answer I was looking for. The above example is for sdbox, mdbox should be exactly the same, am I right?

Yep.

>>>    - The previous question applies to sdbox and mdbox. In the case of mdbox, we can configure rotation of files using /mdbox_rotate_size/ . We would like to rotate daily, not based in size (our users ask us for yesterday's backup). How can we accomplish this?
>> mdbox_rotate_interval = 1d
> 
>    Any known issues with mdbox and zlib plugin in lda & imap?

I don't think so.

> I have read about mbox is /"read-only"/ with zlib plugin. What about mdbox with a high rotate interval (almost a mbox)? How does this work? Is the entire mdbox file loaded into ram and decompressed or a temp file in the filesystem is used?

No, individual messages are compressed inside the file. No temp files or anything. No read only.

>    Another question: any hint about the "hot spot" of size for /mdbox_rotate_interval/?

Its main point of that is to enable daily incremental backups. If you don't want that, I'd say keep it disabled.

>>> We think that mdbox can help us in this. Does anybody has good experiences migrating from maildir->mdox in "large" enviroments? What about mdox performance&  reliability?
>> I haven't recently heard of corruption complaints about mdbox.. Previously when there were those, I didn't hear of complains about losing mails or anything, so that's good :)
> 
>    Any additional comments about this? We are seriously thinking about migrating to mdbox, but is always scary "to be the first one"


I know there is at least one company using mdbox for I think a few hundred people, and they've been reporting me bugs. A lot of that was actually caused by glusterfs I think, so the problems probably weren't as bad as I thought.

I've also been using mdbox for my own mails for about a year with zero problems.

You can of course start a partial conversion. First convert a couple of people to mdbox. After a few weeks convert a few hundred and see how it goes over a few months. If you encounter problems, convert back to maildir. dsync should make all of this pretty easy.