nota-tuning-os-kernel.txt

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Ref: https://www.vultr.com/docs/how-to-deploy-google-bbr-on-centos-7

yum install byobu openssh fail2ban httpd



rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

yum install https://www.elrepo.org/elrepo-release-7.el7.elrepo.noarch.rpm

yum --enablerepo=elrepo-kernel install kernel-ml -y

sudo egrep ^menuentry /etc/grub2.cfg | cut -f 2 -d \'


(0 kerana kernel tu baris pertama, jika baris 2 tukar 1)

sudo grub2-set-default 0

masukkan sysctl.conf

# https://bl.ocks.org/magnetikonline/2760f98f6bf654d5ad79

vm.max_map_count=262144

#Untuk large file transfer

# Increase size of file handles and inode cache
fs.file-max = 3261780

# increase TCP max buffer size
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216

# increase Linux autotuning TCP buffer limits
# min, default, and max number of bytes to use
# per-socket receive/send buffers for TCP [min default max]
net.ipv4.tcp_rmem = 4096 12582912 16777216
net.ipv4.tcp_wmem = 4096 12582912 16777216
#net.ipv4.tcp_rmem = 4096 87380 16777216
#net.ipv4.tcp_wmem = 4096 65536 16777216
#net.ipv4.tcp_rmem = 4096 16060 262144
#net.ipv4.tcp_wmem = 4096 16384 262144

# don't cache ssthresh from previous connection
net.ipv4.tcp_no_metrics_save = 1

# Do less swapping
vm.swappiness = 1

# Linux TCP BBR congestion control
#net.core.default_qdisc=fq
# bbr + fq_codel for kernel >= 4.13
net.core.default_qdisc = fq_codel
net.ipv4.tcp_congestion_control=bbr

###net.ipv4.tcp_notsent_lowat = 16384

net.ipv4.tcp_mtu_probing=1

# Example server: 8 cores
net.core.netdev_max_backlog = 32768

# SYN Backlog Queue, number of half-open connections
net.ipv4.tcp_max_syn_backlog = 32768

# Accept Queue Limit, maximum number of established
# connections waiting for accept() per listener.
net.core.somaxconn = 65535

# Maximum number of SYN and SYN+ACK retries before
# packet expires.
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_synack_retries = 1

# Timeout in seconds to close client connections in
# TIME_WAIT after receiving FIN packet.
net.ipv4.tcp_fin_timeout = 30

# Disable SYN cookie flood protection
net.ipv4.tcp_syncookies = 0

# port range used by TCP and UDP to choose the local port
# default: net.ipv4.ip_local_port_range = 32768 60999
net.ipv4.ip_local_port_range = 1024 61000

# various timewait socket setting tweaks
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_max_tw_buckets = 400000
net.ipv4.tcp_max_orphans = 60000

====

/etc/security/limits.conf

apache soft nofile 64000
apache hard nofile 64000
apache soft nproc 64000
apache hard nproc 64000

====

/etc/sysconfig/memcached

PORT="11211"
USER="memcached"
MAXCONN="8192"
CACHESIZE="16384"
OPTIONS="-l 127.0.0.1 -U 0"


====

yum -y install libhugetlbfs libhugetlbfs-utils

hugeadm --page-sizes-all

hugeadm --page-sizes

grep Hugepagesize /proc/meminfo

hugeadm --list-all-mounts

hugeadm --pool-list

hugeadm --pool-pages-min 2MB:4096

hugeadm --pool-pages-max 2MB:12850

hugeadm --pool-list



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DISABLED

echo never > /sys/kernel/mm/transparent_hugepage/enabled
echo never > /sys/kernel/mm/transparent_hugepage/defrag

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