Difference between revisions of "Centos-optimization"

__NOTOC__

= CentOS Optimizations =

== Disk ==

In order to speedup the disk management, some values are added to each `ext3` partition on the terminal.

The reference site is located at [http://wiki.centos.org/HowTos/Disk_Optimization]

<pre><nowiki>

LABEL=/ / ext3 defaults,noatime,data=writeback,commit=120 1 1

tmpfs /dev/shm tmpfs defaults 0 0

devpts /dev/pts devpts gid=5,mode=620 0 0

sysfs /sys sysfs defaults 0 0

proc /proc proc defaults 0 0

/hpswap swap swap defaults 0 0

</nowiki></pre>

==== noatime ====

Don't write access time

==== data=writeback ====

The data order is not preserved when writes to disk. just after set this value and before restart the terminal run the following command to avoid goes into read-only mode.

<pre><nowiki>

tune2fs -o +journal_data_writeback /dev/hda1

</nowiki></pre>

==== commit=120 ====

Set the time to sync data and metadata.

= System Optimizations =

In `/etc/sysctl.conf` set the vualue

<pre><nowiki>

kernel.shmmax = 63554432

</nowiki></pre>

to increase ''Maximum shared segment''.

== Boot optimizations ==

Reduce boot time passing the known values to the kernel, the site that references this optimizations can be found at [http://free-electrons.com/doc/embedded_linux_optimizations/img0.html]

<pre><nowiki>

# grub.conf generated by anaconda

#

# Note that you do not have to rerun grub after making changes to this file

# NOTICE: You do not have a /boot partition. This means that

# all kernel and initrd paths are relative to /, eg.

# root (hd0,0)

# kernel /boot/vmlinuz-version ro root=/dev/hda1

# initrd /boot/initrd-version.img

#boot=/dev/hda

default=0

timeout=0

splashimage=(hd0,0)/boot/grub/splash.xpm.gz

hiddenmenu

password --md5 $1$/omJBwhD$phlKUXHDZI6BMLkNSfNgD/

title uWink

root (hd0,0)

kernel /boot/vmlinuz-2.6.18-53.el5 ro root=LABEL=/ rhgb vga=792 lpj=998235 reboot=soft quiet

initrd /boot/initrd-2.6.18-53.el5.img

</nowiki></pre>

==== lpj ====

Loops per jiffy can be obtained from `/var/log/messages`

==== reboot=soft ====

When reboots, the firmware will be skipped.

==== quiet ====

Doesn't log all the boot messages to the `stdout`