NFS/RPC slot tuning and high file descriptor limits for storage

sysctl.conf

# Generated by https://www.enginyring.com/tools/sysctl.php
# Optimized sysctl.conf for File Server
# Hardware: 4 cores / 8 threads, 16GB RAM, 1000Mb/s NIC, HDD (not SSD/NVMe)
# Last rev: v1.5.8/26092025
#
# For Debian-based systems:
#   1. Save this file to /etc/sysctl.conf
#   2. Apply immediately with: sudo sysctl -p
# 
# For RHEL-based systems:
#   1. Save this file to /etc/sysctl.d/99-custom.conf
#   2. Apply immediately with: sudo sysctl -p /etc/sysctl.d/99-custom.conf
#   3. Ensure it loads at boot: sudo systemctl restart systemd-sysctl
#
# IMPORTANT: Test these settings with your specific workload.
#
net.core.rmem_max = 6144000
net.core.wmem_max = 6144000
net.core.rmem_default = 2048000
net.core.wmem_default = 2048000
net.core.optmem_max = 2097152
net.ipv4.tcp_rmem = 786432 3145728 6291456
net.ipv4.tcp_wmem = 786432 3145728 6291456
net.ipv4.udp_mem = 786432 3145728 6291456
net.ipv4.tcp_mem = 786432 3145728 6291456
net.ipv4.udp_rmem_min = 16384
net.ipv4.udp_wmem_min = 16384
net.core.netdev_max_backlog = 30000
net.core.somaxconn = 8192
net.ipv4.tcp_max_syn_backlog = 16384
net.core.busy_poll = 50
net.core.busy_read = 50
net.ipv4.tcp_fastopen = 3
net.ipv4.tcp_notsent_lowat = 16384
net.core.netdev_budget_usecs = 4000
net.core.dev_weight = 64
net.ipv4.tcp_max_tw_buckets = 2000000
net.ipv4.ip_local_port_range = 1024 65535
net.ipv4.tcp_congestion_control = bbr
net.core.default_qdisc = fq
net.ipv4.tcp_window_scaling = 1
net.ipv4.tcp_timestamps = 1
net.ipv4.tcp_sack = 1
net.ipv4.tcp_dsack = 1
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_fin_timeout = 10
net.ipv4.tcp_keepalive_time = 300
net.ipv4.tcp_keepalive_intvl = 10
net.ipv4.tcp_keepalive_probes = 6
net.ipv4.tcp_moderate_rcvbuf = 1
net.ipv4.tcp_frto = 2
net.ipv4.tcp_mtu_probing = 1
net.ipv4.conf.all.rp_filter = 1
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.netfilter.nf_conntrack_max = 131072
kernel.sched_min_granularity_ns = 600000
kernel.sched_wakeup_granularity_ns = 800000
kernel.sched_latency_ns = 4000000
kernel.sched_rt_runtime_us = 980000
kernel.sched_migration_cost_ns = 120000
kernel.sched_autogroup_enabled = 0
kernel.sched_cfs_bandwidth_slice_us = 3000
vm.swappiness = 15
vm.dirty_ratio = 5
vm.dirty_background_ratio = 2
vm.dirty_expire_centisecs = 1000
vm.dirty_writeback_centisecs = 100
vm.zone_reclaim_mode = 0
vm.min_free_kbytes = 65536
vm.vfs_cache_pressure = 50
vm.overcommit_memory = 0
vm.overcommit_ratio = 50
vm.max_map_count = 1048576
vm.page-cluster = 0
vm.oom_kill_allocating_task = 1
fs.file-max = 16000000
fs.nr_open = 3200000
fs.aio-max-nr = 65536
fs.inotify.max_user_instances = 1024
fs.inotify.max_user_watches = 1048576
kernel.pid_max = 131072
net.ipv6.conf.all.disable_ipv6 = 1
net.ipv6.conf.default.disable_ipv6 = 1
net.ipv6.conf.lo.disable_ipv6 = 1
sunrpc.tcp_slot_table_entries = 16384
sunrpc.udp_slot_table_entries = 8192

Generated by https://www.enginyring.com/tools/sysctl.php