increase linux file descriptors

increase linux file descriptors

Check Installing CentOS 6.2 on VMware and mounting partitions with noatime posts.

This is very important performance tuning for any web server more information here

#adduser www first
ulimit -n unlimited - www
#check default number of concurrently open file descriptors 
cat /proc/sys/fs/file-max
#set the number to high value depending on server config
echo '1773914' > /proc/sys/fs/file-max
echo 'fs.file-max=1773914' >> /etc/sysctl.conf
/sbin/sysctl -w fs.file-max=1773914

Mounting partitions with noatime

Check Installing CentOS 6.2 on VMware and increase linux file descriptors posts.

This should help reduce disk IO by telling the system not to update inode access times. more here

vi /etc/fstab
#add noatime to the options of the / file system ex:
/dev/mapper/vg_centos6-lv_root /                       ext4    defaults,noatime         1 1

– remount file system

mount -o remount /
cat /proc/mounts | grep noatime

Change SSH port and enable X11 forwarding

Check Installing CentOS 6.2 on VMware post.

– configure ssh port

cp /etc/ssh/sshd_config /etc/ssh/sshd_config.old
vi /etc/ssh/sshd_config
#uncomment port 22 and change to
port 4568

– enable X11 forwarding

#install needed libraries
yum -y install xorg-x11-xauth xorg-x11-fonts-base liberation-fonts

vi /etc/ssh/sshd_config
X11Forwarding yes
X11DisplayOffset 10
X11UseLocalhost yes

– restart sshd

 /etc/init.d/sshd restart

Now you should connect to

Configuring iptables on CentOS

– disable SELINUX

vi /etc/selinux/config

– reboot or run

 setenforce 0

– add iptables rules

Change server hostname

Check Installing CentOS 6.2 on VMware post.

Adding Hostname to Linux server

vi /etc/hosts
# add  localhost.localdomain localhost centos6.vmware.local
vi /etc/sysconfig/network
hostname centos6.vmware.local