slow transfers on webshare service

[Miroslav Valenta]

Hi 

i have problem with slow transfers on my web filesharing server. I'm
running FreeBSD 6.2 

files are sending by lighttpd 1.4.18 :

server.max-worker = 8
server.max-fds = 8192
server.network-backend = "writev"

-----

HW:
xeon 3160 
4GB of RAM
areca arc-1260 disk controller with 1GB cache + 8x 500GB sata2 hdd


file transfers slow down when i'm about 500 downloading connections

but when i send same file from same storage by same line it's  sending
fast.

i think it must be something about lighttpd or sysctl tunning.



Can you help me pls?