radwho so slow..

Hi,

I actually have 2 problems and I can't seem to find very much information on this...

1.  Each time I do a radwho, it's very slow - it takes abou 5 to 10 minutes to show everyone who is logged in.  Is this normal, if so why?  

2.  We sometimes fail to receive accounting packets when someone disconnects.  Our limit of connections is 4.  So, instead of doing a radzap on each individual person, we simply delete the radutmp file - is this a problem?

Martin