I have had squid installed a while and tonight it is behaving very sluggishly.
ANy ideas what I can do to check the problem?
It doesn;t seem it is memory.
Could be bandwidth related but I am getting could not connect errors from squid and then occasionally it connects but if it was bandwidth it would just be slowloading.
httpd works fine, so does openvpn, and ssh, so must be a squid issue.

There is no syn or ddos and I have about 120 connections.

I have each use limited to 1Mb so really doubt a bandwidth issue...
[root ]# netstat -nat | grep :80 | grep ESTABLISHED| wc -l
84
[root ]# netstat -nat | grep :8080 | grep ESTABLISHED| wc -l
57

CPU load averages 0.05 (1 min) 0.03 (5 mins) 0.00 (15 mins)
Real memory 928.13 MB total, 254.31 MB used

Virtual memory 509.84 MB total, 7.41 MB used

Local disk space 232.06 GB total, 14.23 GB used

What are the rules in the squid conf file? I had a similar problem a while back and it was related to poorly written rules causing excessive CPU usage on the server.

It's possible but it only started up after about 2 months uptime so it's unlikely that the rules might have caused a bottleneck somewhere.
It does seem like conincidence that a server reboot fixed it though.