Compression: all or nothing?

[Patrick Domack]

It's because it doesn't move email by email to alt storage, but the  
whole file. So the emails move as is, be them compressed or  
uncompressed.

I think you could do what you want, but passing the correct options,  
but I don't think it would be easy to do.

I would just store them compressed all the time, saves disk space, io  
bandwidth, and if it goes over the network, actually will give a huge  
performance improvement.

I have moved all mine to zstd currently, from gzip I had been using  
since it was possible.


Quoting Alex King <alex at king.net.nz>:

> Using 2.3.13 (89f716dc2) (debian package), with mdbox storage.
>
> I considering adding the zlib plugin.  I understand that reading  
> mail can cope with either compressed or uncompressed mailboxes.
>
> I'm wondering if I can leave the main storage uncompressed, while  
> having the alternate storage compressed.  There does not seem to be  
> a way to configure this, from  
> https://doc.dovecot.org/settings/plugin/zlib-plugin/ it seems  
> compression (on saving emails) is an all-or-nothing option?
>
> Can I leave zlib_save unset in my main configuration, and have  
> doveadm use some alternate configuration with zlib_save set?  It  
> doesn't look hopeful because I don't see the ability to use a  
> different config at https://wiki.dovecot.org/Tools/Doveadm/Altmove.
>
> Perhaps I would need multiple copies of the daemon running?
>
> Or is it better just to compress everything?  I plan to store older  
> mails (perhaps 3months+) in the alternative storage, and was  
> thinking it would be nice to have those compressed, while I don't  
> need to compress the main store.
>
> Any feedback welcome.
>
> Thanks,
> Alex