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Kernel Tuning
This tuning i have used for dedicated DB server.
You can use it, as it is on any modern server, but please make sure to read note once.
###### Optimization Dec. 22 2011 ######
## Reduce Swapping
vm.swappiness = 30 vm.dirty_ratio = 50 vm.dirty_background_ratio = 5
## Prevent Syn Attack
net.ipv4.tcp_syncookies = 1 net.ipv4.tcp_syn_retries = 5 net.ipv4.tcp_synack_retries = 2 net.ipv4.tcp_max_syn_backlog = 4096
## Enable IP Spoofing Protection
net.ipv4.conf.all.rp_filter = 1 net.ipv4.conf.default.rp_filter = 1
## Decrease tcp fin timeout
net.ipv4.tcp_fin_timeout = 15
## Decrease the time default value for keep alive
net.ipv4.tcp_keepalive_time = 300 net.ipv4.tcp_keepalive_probes = 5 net.ipv4.tcp_keepalive_intvl = 15
## Enable Fix for RFC1337
net.ipv4.tcp_rfc1337 = 1
<notes warning> ## Not for Low memory system </notes>
## Increase Read Buffer
net.ipv4.tcp_rmem = “8192 87380 16777216” net.ipv4.udp_rmem_min = 16384 net.core.rmem_default = 131072 net.core.rmem_max = 16777216
## Increase Write Buffer
net.ipv4.tcp_wmem = “8192 65536 16777216” net.ipv4.udp_wmem_min = 16384 net.core.wmem_default = 131072 net.core.wmem_max = 16777216
## Increase Number of incocimng connections
net.core.somaxconn = 32768
## Increase max buffer for con.
net.core.optmem_max = 65536
## Increase TCP queue lenght
net.ipv4.neigh.default.proxy_qlen = 96 net.ipv4.neigh.default.unres_qlen = 6
## increase slots for tcp / udp
sunrpc.tcp_slot_table_entries = 32 sunrpc.udp_slot_table_entries = 32
## increase uRPC datagram queue lenght
net.unix.max_dgram_qlen = 50
