As I have mentioned before I am working on creating various Fedora server loads at http://www.packetstorm.org/fedprj/ So far I have the core load done and I am almost done with the log server load http://www.packetstorm.org/fedprj/core/log_server.htm While looking into network performance tuning options, I ran across the following setting tweaks that could be made on the system net.ipv4.tcp_rmem = 10000000 10000000 10000000, sets min/default/max TCP read buffer, default 4096 87380 174760 net.ipv4.tcp_wmem = 10000000 10000000 10000000, sets min/pressure/max TCP write buffer, default 4096 16384 131072 net.ipv4.tcp_mem = 10000000 10000000 10000000, sets min/pressure/max TCP buffer space, default 31744 32256 32768 net.ipv4.tcp_sack=0 turn SACK support off, default on net.ipv4.tcp_window_scaling = 0, turn TCP window scaling support off, default onnet.core.hot_list_length = 300000, maximum number of skb-heads to be cached, default 128 net.ipv4.tcp_max_tw_buckets = 2000000, sets TCP time-wait buckets pool size, default 180000 net.ipv4.tcp_timestamps=0 turns TCP timestamp support off, default on net.core.rmem_max=524287 maximum receive socket buffer size net.core.wmem_max=524287 maximum send socket buffer size net.core.rmem_default=524287 default receive socket buffer size net.core.wmem_default=524287 default send socket buffer size net.core.optmem_max=524287 maximum amount of option memory buffers, default 10240 net.core.netdev_max_backlog=300000 number of unprocessed input packets before kernel starts dropping them, default 300 For the log server I focused on socket buffers as I noticed that udp packets were getting dumped due to high syslog volume. But does anyone here have a really good explanation on the settings above? Can they be used as a general performance tweak on any system configuration? I read in one place some of these settings should not be used on multi-user systems. Is there a Fedora tuning guide? Any recommendations for a good baseline? Is there a reasoning behind the default Fedora settings listed above? Not that I disagree but that I want to understand it. FYI here is a SPEC doc I found in google where some of these settings were mentioned http://216.239.41.104/search?q=cache:JrEBIcPgWoIJ:www.specbench.org/web99/results/res2002q1/web99-20020205-00174.pdf+net.core.wmem_default%3D&hl=en&ie=UTF-8 thanks Greg
