[Dovecot] Delay email!

I am using postfix + dovecot 2.0.6 + mailman

And others 2 serves with only postfix and dovecot writing at same storage with OCFS2.

We are having problens with IOwait, and still trying to figure out why that is happen!

But, problem becomes much worse when some emails are used in mailman, when it happens all 3 serves became really slow. iowait goes to 80.

Does anyone have an idea how to slow down the dovecot lda ?

I want it to nit to iwrite so much email, at least take a small break between each mail!!

Any ideias?

Thanks!

[]'sf.rique