[imp] Scalability of rate-limiting?

[Andrew Morgan]

On Tue, 6 Oct 2009, Wil Cooley wrote:

>
> We are considering implementing limits on recipients per message and per
> time period using the features that we have now in IMP. We have a fairly
> sizable user base; it's hard to estimate concurrent connnections with
> HTTP being stateless and our IMAP connections being cached with up-
> imapproxyd, but I'd guess we peak around 3k concurrent users across 5
> webmail front-ends.
>
> Assuming we use the SQL driver for permissions and not DataTree, what
> kind of additional overhead should we expect between the permissions
> check and the outgoing e-mail logging?
>
> Are people using these rate-limiting features with sizable installations
> with success?

We use rate-limiting here to control accounts that have been phished (a 
fairly regular occurrence).  I think our installation is very similar in 
size to yours...  We peak around 3k concurrent IMAP connections (most from 
Webmail) and have 3 webmail frontends.  We are still using the Datatree 
though.

Our limit is set to 500 messages per 24 hours, for all users.  I've never 
tried setting per-user limits.

 	Andy