Sysctl.conf large instance

sysctl.conf

fs.file-max = 2097152

# Increase the maximum number of socket connections
net.core.somaxconn = 1024

# Increase the size of the receive queue
net.core.netdev_max_backlog = 5000

# Increase the number of incoming connections
net.core.somaxconn = 4096

# Increase the range of ephemeral ports
net.ipv4.ip_local_port_range = 10240 65535

# Reuse and recycle TIME_WAIT sockets faster
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_tw_recycle = 1

# Enable TCP SYN cookies
net.ipv4.tcp_syncookies = 1

# Increase the number of possible connections
net.ipv4.tcp_max_syn_backlog = 8192

# Swappiness setting to avoid swap unless absolutely necessary
vm.swappiness = 10

# Increase the amount of memory allocated to file handles and inodes
vm.vfs_cache_pressure = 50

net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1

# Enable TCP window scaling
net.ipv4.tcp_window_scaling = 1

# Increase TCP buffer sizes
net.ipv4.tcp_rmem = 4096 87380 6291456
net.ipv4.tcp_wmem = 4096 65536 6291456

# Increase the maximum amount of option memory buffers
net.core.optmem_max = 25165824

kernel.shmmax = 68719476736
kernel.shmall = 4294967296

sudo sysctl -p

Explanation of Common Settings

• fs.file-max: Sets the maximum number of file handles that the kernel will allocate.
• net.core.somaxconn: Maximum number of connections that can be queued for acceptance.
• net.core.netdev_max_backlog: Maximum number of packets, queued on the input side, when the interface receives packets faster than the kernel can process them.
• net.ipv4.ip_local_port_range: Range of ports used for outgoing connections.
• net.ipv4.tcp_tw_reuse and net.ipv4.tcp_tw_recycle: Enable reuse and recycling of TIME_WAIT sockets.
• net.ipv4.tcp_syncookies: Protect against SYN flood attacks.
• net.ipv4.tcp_max_syn_backlog: Maximum number of remembered connection requests, which have not received an acknowledgment from connecting clients.
• vm.swappiness: Controls the tendency of the kernel to move processes out of physical memory and onto the swap disk.
• vm.vfs_cache_pressure: Controls the tendency of the kernel to reclaim the memory which is used for caching of directory and inode objects.
• kernel.shmmax and kernel.shmall: Control the maximum shared memory segment size and total amount of shared memory, respectively.