Networking problem

[gege]

Hi,

we are running FreeBSD 8.0-STABLE, and got problems with network. On one server (web1) we are running heavily loaded lighttpd, which performs as load-balancer for fast cgi. On other server (db1) we are running mysql, memcached, redis...

Problem is, sometimes I see in the log (sometimes is log quite flooded), strange errors for memcached and redis, for example, when I store compressed value in memcached, I get error while decompressing, on redis, sometimes I get it can not connect (memcached detto).

So I think, we have serious problem with network.

I want kindly ask you, if there is some tool, which can test network performance under load, open a lot of connections...I just want to find out where is the problem.

Here are some data (currently both boxes on the minimum load):

database box:
#sockstat -4 | wc -l
     453

#netstat -lan | wc -l
    6526

#netstat -sp tcp | grep -i overflow
        2022 listen queue overflows
                0 bucket overflow
                0 cache overflow
        0 SACK scoreboard overflow

web box:
#sockstat -4 | wc -l
     583

#netstat -lan | wc -l
   29511

#netstat -sp tcp | grep -i overflow
        1053335 listen queue overflows
                0 bucket overflow
                0 cache overflow
        0 SACK scoreboard overflow