[Dovecot] (Single instance) attachment storage with single-dbox

[Timo Sirainen]

On 25.9.2010, at 9.49, Daniel L. Miller wrote:

> On 9/24/2010 11:57 AM, Timo Sirainen wrote:
>> Just a note to myself and whoever else cares, should be added to wiki
>> once it has its own page about this:
>> 
>> With single-dbox messages can be copied with hard linking. This means
>> that there can be multiple files that point to the same attachment file.
>> The attachment is now deleted only once the mail file's link count drops
>> to zero, so this works fine..
> Why is this specific to sdbox?  Does mdbox SIS work differently?

mdbox internally keeps a reference count of how many copies of messages there exists and the attachment isn't deleted until the last reference is gone. So in mdbox even without attachments there exists a bit similar problem: if you manually add/copy mailbox directories the reference counts get messed up.