[pilhuhn]

I completely agree, that this is mailbox dependend.

It is not possible with some databases to determine the amount of storage per user

You mean that you want to store messages until the database chokes at you? And assume that every user has an account in the db? (Might be silly questions, but I did not follow the JBossMail thread too closely).

I would propose to have a configuration file/table where you can put those quotas in, as well as local alias mappings. For example @work I have
heiko.rupp@domain and hrupp@domain as valid email addresses, which both map to the same mailbox.

And no, this is not a request/requirement for M1 :-)

[acoliver]

Eventually I think it should be linked to the UserRepository and the Mailbox. The more I think about it we can just calculate the present message size and store it in the mailbox. We don't need to rely on underlying support. We should support both "safe" and "fast" quotas. Safe quotas are done as a (potentially slow) calculation (select sum(size) from entitymailbox where user=X) and fast quotas maintain a lookup table. The reason one is safe and one is fast is that the lookup table could easily get out of synch.