I realize mbuf's and mbuf clusters are two different statistics, however if they are completely separate from each other then can anybody explain why when the kern.ipc.nmbufs limit reached error occurs the mbufs in use are always just over the limit set for mbuf clusters? For instance, when I had mbuf clusters set to 1,000,000 the error showed 1,033,130 mbufs in use. When I had it set to 200,000, it showed just over 200,000 mbufs in use when the issue occurred. Are you certain these two are not related? It seems to me that increasing the clusters increases the number of mbufs that can be used (which would make sense to me, but I am not an expert in this field).
As of right now I have increased memory from 768 to 1024 and the firewall has gone several days without an issue. Typically the issue would have occurred several times a day. I am hopeful that this is a suitable solution, or at the very least a way to extend the time between occurrences. If it occurs again I will increase to 1280 or 1536.