[horde] splitting a email export

[Gregor Bothe]

Hi all,

we want to change our quota limit and therefor inform our users 
regarding their current allocated space. Further we have to tell some 
users to clean their inboxes by exporting and deleting emails.

Unfortunately it seems like the Horde 5.2.12 email export function dumps 
a complete export into the system memory and uses the PHP memory_limit - 
quite a problem, if the inbox is 20G (mdir). We could increase the 
limit, but I would prefer an option to split an export into different 
files or "bypassing" the system memory somehow.
Or any other option to allow the user to export their emails as a mbox 
file by an easy end-user usable function/application (I know about e.g. 
Thunderbird client plugin - but I don't want to tell them, to install a 
full email client just for an export).

I'm looking forward to any kind of help :)
Thanks in advance. Regards,

Greg