# Database kernel optimisation
fs.aio-max-nr = 1048576 # 限制并发未完成的异步请求数目，，不应小于1M
fs.file-max = 16777216 # 最大打开16M个文件
# kernel
kernel.shmmax = 485058 # 共享内存最大页面数量: $(expr $(getconf _PHYS_PAGES) / 2)
kernel.shmall = 1986797568 # 共享内存总大小： $(expr $(getconf _PHYS_PAGES) / 2 \* $(getconf PAGE_SIZE))
kernel.shmmni = 16384 # 系统范围内共享内存段的最大数量 4096 -> 16384
kernel.msgmni = 32768 # 系统的消息队列数目,影响可以启动的代理程序数 设为内存MB数
kernel.msgmnb = 65536 # 影响队列的大小
kernel.msgmax = 65536 # 影响队列中可以发送的消息的大小
kernel.numa_balancing = 0 # Numa禁用
kernel.sched_migration_cost_ns = 5000000 # 5ms内，调度认为进程还是Hot的。
kernel.sem = 2048 134217728 2048 65536 # 每个信号集最大信号量2048，系统总共可用信号量134217728，单次最大操作2048，信号集总数65536
# vm
vm.dirty_ratio = 80 # 绝对限制，超过80%阻塞写请求刷盘
vm.dirty_background_bytes = 268435456 # 256MB脏数据唤醒刷盘进程
vm.dirty_expire_centisecs = 6000 # 1分钟前的数据被认为需要刷盘
vm.dirty_writeback_centisecs= 500 # 刷新进程运行间隔5秒
vm.mmap_min_addr = 65536 # 禁止访问0x10000下的内存
vm.zone_reclaim_mode = 0 # Numa禁用
# vm swap
vm.swappiness = 0 # 禁用SWAP，但高水位仍会有
vm.overcommit_memory = 2 # 允许一定程度的Overcommit
vm.overcommit_ratio = 50 # 允许的Overcommit:$((($mem - $swap) * 100 / $mem))
# tcp memory
net.ipv4.tcp_rmem = 8192 65536 16777216 # tcp读buffer: 32M/256M/16G
net.ipv4.tcp_wmem = 8192 65536 16777216 # tcp写buffer: 32M/256M/16G
net.ipv4.tcp_mem = 131072 262144 16777216 # tcp 内存使用 512M/1G/16G
net.core.rmem_default = 262144 # 接受缓冲区默认大小: 256K
net.core.rmem_max = 4194304 # 接受缓冲区最大大小: 4M
net.core.wmem_default = 262144 # 发送缓冲区默认大小: 256K
net.core.wmem_max = 4194304 # 发送缓冲区最大大小: 4M
# tcp keepalive
net.ipv4.tcp_keepalive_intvl = 20 # 探测没有确认时，重新发送探测的频度。默认75s -> 20s
net.ipv4.tcp_keepalive_probes = 3 # 3 * 20 = 1分钟超时断开
net.ipv4.tcp_keepalive_time = 60 # 探活周期1分钟
# tcp port resure
net.ipv4.tcp_tw_reuse = 1 # 允许将TIME_WAIT socket用于新的TCP连接。默认为0
net.ipv4.tcp_tw_recycle = 0 # 快速回收，已弃用
net.ipv4.tcp_fin_timeout = 5 # 保持在FIN-WAIT-2状态的秒时间
net.ipv4.tcp_timestamps = 1
# tcp anti-flood
net.ipv4.tcp_syncookies = 1 # SYN_RECV队列满后发cookie，防止恶意攻击
net.ipv4.tcp_synack_retries = 1 # 收到不完整sync后的重试次数 5->2
net.ipv4.tcp_syn_retries = 1 #表示在内核放弃建立连接之前发送SYN包的数量。
# tcp load-balancer
net.ipv4.ip_forward = 1 # IP转发
net.ipv4.ip_nonlocal_bind = 1 # 绑定非本机地址
net.netfilter.nf_conntrack_max = 1048576 # 最大跟踪连接数
net.ipv4.ip_local_port_range = 10000 65535 # 端口范围
net.ipv4.tcp_max_tw_buckets = 262144 # 256k TIME_WAIT
net.core.somaxconn = 65535 # 限制LISTEN队列最大数据包量，触发重传机制。
net.ipv4.tcp_max_syn_backlog = 8192 # SYN队列大小：1024->8192
net.core.netdev_max_backlog = 8192 # 网卡收包快于内核时，允许队列长度# kernel
kernel.shmmax = 485058 # 共享内存最大页面数量: $(expr $(getconf _PHYS_PAGES) / 2)
kernel.shmall = 1986797568 # 共享内存总大小： $(expr $(getconf _PHYS_PAGES) / 2 \* $(getconf PAGE_SIZE))
kernel.shmmni = 16384 # 系统范围内共享内存段的最大数量 4096 -> 16384
kernel.msgmni = 32768 # 系统的消息队列数目,影响可以启动的代理程序数 设为内存MB数
kernel.msgmnb = 65536 # 影响队列的大小
kernel.msgmax = 65536 # 影响队列中可以发送的消息的大小
kernel.numa_balancing = 0 # Numa禁用
kernel.sched_migration_cost_ns = 5000000 # 5ms内，调度认为进程还是Hot的。
kernel.sem = 2048 134217728 2048 65536 # 每个信号集最大信号量2048，系统总共可用信号量134217728，单次最大操作2048，信号集总数65536# vm
vm.dirty_ratio = 80 # 绝对限制，超过80%阻塞写请求刷盘
vm.dirty_background_bytes = 268435456 # 256MB脏数据唤醒刷盘进程
vm.dirty_expire_centisecs = 6000 # 1分钟前的数据被认为需要刷盘
vm.dirty_writeback_centisecs= 500 # 刷新进程运行间隔5秒
vm.mmap_min_addr = 65536 # 禁止访问0x10000下的内存
vm.zone_reclaim_mode = 0 # Numa禁用
# vm swap
vm.swappiness = 0 # 禁用SWAP，但高水位仍会有
vm.overcommit_memory = 2 # 允许一定程度的Overcommit
vm.overcommit_ratio = 50 # 允许的Overcommit:$((($mem - $swap) * 100 / $mem))# tcp memory
net.ipv4.tcp_rmem = 8192 65536 16777216 # tcp读buffer: 32M/256M/16G
net.ipv4.tcp_wmem = 8192 65536 16777216 # tcp写buffer: 32M/256M/16G
net.ipv4.tcp_mem = 131072 262144 16777216 # tcp 内存使用 512M/1G/16G
net.core.rmem_default = 262144 # 接受缓冲区默认大小: 256K
net.core.rmem_max = 4194304 # 接受缓冲区最大大小: 4M
net.core.wmem_default = 262144 # 发送缓冲区默认大小: 256K
net.core.wmem_max = 4194304 # 发送缓冲区最大大小: 4M
# tcp keepalive
net.ipv4.tcp_keepalive_intvl = 20 # 探测没有确认时，重新发送探测的频度。默认75s -> 20s
net.ipv4.tcp_keepalive_probes = 3 # 3 * 20 = 1分钟超时断开
net.ipv4.tcp_keepalive_time = 60 # 探活周期1分钟
# tcp port resure
net.ipv4.tcp_tw_reuse = 1 # 允许将TIME_WAIT socket用于新的TCP连接。默认为0
net.ipv4.tcp_tw_recycle = 0 # 快速回收，已弃用
net.ipv4.tcp_fin_timeout = 5 # 保持在FIN-WAIT-2状态的秒时间
net.ipv4.tcp_timestamps = 1
# tcp anti-flood
net.ipv4.tcp_syncookies = 1 # SYN_RECV队列满后发cookie，防止恶意攻击
net.ipv4.tcp_synack_retries = 1 # 收到不完整sync后的重试次数 5->2
net.ipv4.tcp_syn_retries = 1 #表示在内核放弃建立连接之前发送SYN包的数量。
# tcp load-balancer
net.ipv4.ip_forward = 1 # IP转发
net.ipv4.ip_nonlocal_bind = 1 # 绑定非本机地址
net.netfilter.nf_conntrack_max = 1048576 # 最大跟踪连接数
net.ipv4.ip_local_port_range = 10000 65535 # 端口范围
net.ipv4.tcp_max_tw_buckets = 262144 # 256k TIME_WAIT
net.core.somaxconn = 65535 # 限制LISTEN队列最大数据包量，触发重传机制。
net.ipv4.tcp_max_syn_backlog = 8192 # SYN队列大小：1024->8192
net.core.netdev_max_backlog = 8192 # 网卡收包快于内核时，允许队列长度
fs.aio-max-nr = 1048576 # 限制并发未完成的异步请求数目，，不应小于1M
fs.file-max = 16777216 # 最大打开16M个文件针对PostgreSQL，可以对Linux操作系统进行调优，具体包括：
- IO优化：调度算法调优，预读参数
- 内存优化：关闭SWAP，关闭透明大页，关闭NUMA。
- 资源限制
optimize() {
if (( "$#" == 1 )); then
local datadir="$1"; shift
local mem="$(free \
| awk '/Mem:/{print $2}')"
local swap="$(free \
| awk '/Swap:/{print $2}')"
cat > /etc/sysctl.conf <<- EOF
# Database kernel optimisation
fs.aio-max-nr = 1048576
fs.file-max = 76724600
kernel.sem = 4096 2147483647 2147483646 512000
kernel.shmmax = $(( $mem * 1024 / 2 ))
kernel.shmall = $(( $mem / 5 ))
kernel.shmmni = 819200
net.core.netdev_max_backlog = 10000
net.core.rmem_default = 262144
net.core.rmem_max = 4194304
net.core.wmem_default = 262144
net.core.wmem_max = 4194304
net.core.somaxconn = 4096
net.ipv4.tcp_max_syn_backlog = 4096
net.ipv4.tcp_keepalive_intvl = 20
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.tcp_keepalive_time = 60
net.ipv4.tcp_mem = 8388608 12582912 16777216
net.ipv4.tcp_fin_timeout = 5
net.ipv4.tcp_synack_retries = 2
net.ipv4.tcp_syncookies = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_tw_recycle = 0
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_tw_buckets = 262144
net.ipv4.tcp_rmem = 8192 87380 16777216
net.ipv4.tcp_wmem = 8192 65536 16777216
vm.dirty_background_bytes = 409600000
net.ipv4.ip_local_port_range = 40000 65535
vm.dirty_expire_centisecs = 6000
vm.dirty_ratio = 80
vm.dirty_writeback_centisecs = 50
vm.extra_free_kbytes = 4096000
vm.min_free_kbytes = 2097152
vm.mmap_min_addr = 65536
vm.swappiness = 0
vm.overcommit_memory = 2
vm.overcommit_ratio = $(( ( $mem - $swap ) * 100 / $mem ))
vm.zone_reclaim_mode = 0
EOF
sysctl -p
cat > /etc/security/limits.d/postgresql.conf <<- EOF
postgres soft nproc 655360
postgres hard nproc 655360
postgres hard nofile 655360
postgres soft nofile 655360
postgres soft stack unlimited
postgres hard stack unlimited
postgres soft core unlimited
postgres hard core unlimited
postgres soft memlock 250000000
postgres hard memlock 250000000
EOF
cat > /etc/security/limits.d/pgbouncer.conf <<- EOF
pgbouncer soft nproc 655360
pgbouncer hard nofile 655360
pgbouncer soft nofile 655360
pgbouncer soft stack unlimited
pgbouncer hard stack unlimited
pgbouncer soft core unlimited
pgbouncer hard core unlimited
pgbouncer soft memlock 250000000
pgbouncer hard memlock 250000000
EOF
cat > /etc/security/limits.d/pgpool.conf <<- EOF
pgpool soft nproc 655360
pgpool hard nofile 655360
pgpool soft nofile 655360
pgpool soft stack unlimited
pgpool hard stack unlimited
pgpool soft core unlimited
pgpool hard core unlimited
pgpool soft memlock 250000000
pgpool hard memlock 250000000
EOF
fi
}