mbuf clusters

[Dave Raven]

Hi all, 

    I have a FreeBSD box running a squid cache, 
    FreeBSD 4.7-RELEASE-p9 i386, squid built 
    from latest ports. (2.5-STABLE1). I'm not absolutely
    sure, but it appears that whenever I am running squid, 
    the mbuf clusters on the bsd box rise at a steady rate, 
    before reaching the limit, and the box's network failing 
    to work. The box is under very small load and this 
    is certainly not expected behaviour (I also have mbuf 
    clusters set at 33280). I know this is not neccessarily 
    a FreeBSD related question, but I am wondering how 
    I can find out what it is that is using up the mbuf clusters 
    without freeing them, as they steadily raise until they 
    reach the max... How can I obtain more information 
    about the mbuf cluster usage? (right now I'm just 
    using netstat -m) Is there a way to force clearing them?
    Or to flush inactive usage, or anything?

    Quite lost here.

Thanks
Dave