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Performance related settings
- OS tuning
# OS swaping behavior. vm.swappiness = 0 mean no swaping
vm.swappiness = 0
# kernel behavior with regard to the dirty pages
vm.dirty_background_ratio = $vm_dirty_bg_ratio
vm.dirty_ratio = $vm_dirty_ratio
- Network tuning
# Basic TCP tuning
net.ipv4.tcp_keepalive_time = 600
net.ipv4.tcp_synack_retries = 3
net.ipv4.tcp_syn_retries = 3
# Enable a fix for RFC1337 - time-wait assassination hazards in TCP
net.ipv4.tcp_rfc1337 = 1
# Minimum interval between garbage collection passes This interval is
# in effect under high memory pressure on the pool
net.ipv4.inet_peer_gc_mintime = 5
# Enable window scaling as defined in RFC1323
net.ipv4.tcp_window_scaling = 1
# Enable select acknowledgments
net.ipv4.tcp_sack = 1
# Enable FACK congestion avoidance and fast retransmission
net.ipv4.tcp_fack = 1
# Allows TCP to send "duplicate" SACKs
net.ipv4.tcp_dsack = 1
# Enable fast recycling TIME-WAIT sockets
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_max_syn_backlog = 20000
# tells the kernel how many TCP sockets that are not attached
# to any user file handle to maintain
net.ipv4.tcp_max_orphans = $max_orphan
# maximum number of sockets in TIME-WAIT to be held simultaneously
net.ipv4.tcp_max_tw_buckets = $max_tw
# don't cache ssthresh from previous connection
net.ipv4.tcp_no_metrics_save = 1
net.ipv4.tcp_moderate_rcvbuf = 1
# increase Linux autotuning TCP buffer limits
net.ipv4.tcp_rmem = 4096 87380 33554432
net.ipv4.tcp_wmem = 4096 65536 33554432
# increase TCP max buffer (bytes)
net.core.rmem_max = 67108864
net.core.wmem_max = 67108864
net.core.netdev_max_backlog = 30000
net.core.somaxconn = 65000
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Resources related settings
# required free memory
vm.min_free_kbytes = $min_free
# system open file limit
fs.file-max = $file_max
# Maximum shared segment size in bytes
kernel.shmmax = $shmmax
#
# Maximum number of shared memory segments in pages
kernel.shmall = $shmall
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Security related settings
# Network security hardening
kernel.exec-shield = 1
kernel.randomize_va_space = 2
net.ipv4.ip_forward = 0
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.all.accept_source_route = 0
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
net.ipv4.conf.all.log_martians = 1
net.ipv4.conf.default.log_martians = 1
net.ipv4.icmp_echo_ignore_broadcasts = 1
net.ipv4.icmp_ignore_bogus_error_responses = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.tcp_syncookies = 1
General settings
# Defines the local port range that is used by TCP and UDP
net.ipv4.ip_local_port_range = 1024 65535
# Enable timestamps (RFC1323)
net.ipv4.tcp_timestamps = 1
Limits configuration( /etc/security/limits.conf )
* hard nofile 125000
* soft nofile 125000
root hard nofile 400000
root soft nofile 400000