SC3 kernel tweaks
From GridPP Wiki
These are the sysctl settings which are a good starting point for tuning file transfer rates.
### IPV4 specific settings net.ipv4.tcp_timestamps = 0 # turns TCP timestamp support off, default 1, reduces CPU use net.ipv4.tcp_sack = 1 # turn SACK support off, default on # on systems with a VERY fast bus -> memory interface this is the big gainer net.ipv4.tcp_rmem = 4096 262144 1048576 # sets min/default/max TCP read buffer, default 4096 87380 174760 net.ipv4.tcp_wmem = 4096 262144 1048576 # sets min/pressure/max TCP write buffer, default 4096 16384 131072 #net.ipv4.tcp_mem = 262144 4194304 8388608 # sets min/pressure/max TCP buffer space, default 31744 32256 32768 net.ipv4.tcp_mem = 97280 131072 262144 # sets min/pressure/max TCP buffer space, default 31744 32256 32768 ### CORE settings (mostly for socket and UDP effect) net.core.rmem_max = 1048575 # maximum receive socket buffer size, default 131071 net.core.wmem_max = 1048575 # maximum send socket buffer size, default 131071 net.core.rmem_default = 262143 # default receive socket buffer size, default 65535 net.core.wmem_default = 262143 # default send socket buffer size, default 65535 net.core.optmem_max = 262143 # maximum amount of option memory buffers, default 10240 net.core.netdev_max_backlog = 1000 # number of unprocessed input packets before kernel starts dropping them, default 300
To use them, save to a file and do
# sysctl -p SC3-TWEAK-FILE