Re: [Dovecot] Uncompressing dboxes

[Timo Sirainen]

On 1.2.2012, at 17.43, Lauri Alanko wrote:

> I have an mdbox directory that has been created with the zlib plugin active, 
> using bzip2 compression. I would now like to convert these into uncompressed 
> mdbox format. How do I do this? I have tried unsetting all zlib-related 
> configuration options, but dsync still produces compressed mdbox at the other 
> end, too.

Do something like:

dsync backup dsync -o plugin/zlib_save= -o mail=mdbox:/tmp/uncompressed

> (Incidentally, it's a bit funny that when the zlib plugin is enabled, dsync 
> automatically creates compressed dboxes, and even compressed maildirs (which 
> is pretty useless), but not compressed mboxes, although that's where 
> compression would be most beneficial.)

Dovecot supports only read-only compressed mboxes. Also compressed mboxes are 
always pretty slow, since there's no way to quickly jump around in the file (to 
go to offset X, you need to uncompress the first X bytes of the mbox file, 
that's one reason why for mdbox I decided against using full file compression).

[Dovecot] Uncompressing dboxes

[Lauri Alanko]

Hello.

I have an mdbox directory that has been created with the zlib plugin  
active, using bzip2 compression. I would now like to convert these  
into uncompressed mdbox format. How do I do this? I have tried  
unsetting all zlib-related configuration options, but dsync still  
produces compressed mdbox at the other end, too.


I guess I could convert to mbox, and then back to mdbox, but for  
certain reasons I'm not very enthusiastic about doing anything  
mbox-related with dovecot any more.


(Incidentally, it's a bit funny that when the zlib plugin is enabled,  
dsync automatically creates compressed dboxes, and even compressed  
maildirs (which is pretty useless), but not compressed mboxes,  
although that's where compression would be most beneficial.)


Thanks,


Lauri