By taking an example of reading a Linux technical documentation, the slides show how important the Linux fundamental skills are.

1. Importance of Linux System
Fundamental In Technical
Documentation Reading
by
netman<netman@study-area.org>
August 2016

2. The Sample Document
https://access.redhat.com/documentation/en-
US/Red_Hat_Enterprise_Linux/7/pdf/Virtualization_Tuning_and_Optimization_Guide/R
ed_Hat_Enterprise_Linux-7-Virtualization_Tuning_and_Optimization_Guide-en-US.pdf

3. The Basic Requirement
English reading Google searching+

4. Command line & Quoting
Improper line ending
perf kvm --host --guest --guestmodules=guest-modules report -i
perf.data.kvm --force > analyze
Should be:
perf kvm --host --guest --guestmodules=guest-modules report -i perf.data.kvm
--force > analyze
Or:

5. Configuration of sysctl
echo “net.ipv4.conf.all.arp_filter=1” >> /etc/sysctl.conf
sysctl -p
It means:

6. Kernel module management
echo “options vhost_net experimental_zcopytx=1”
> /etc/modprode.d/vhost_net.conf
modprobe –r vhost_net
modprobe vhost_net
Actually you should do:

7. Configuration file path
You have to know about:
• The guest xml path:
/etc/libvirt/qemu/guest_name.xml
OR
• The command to edit guest xml:
virsh edit guest_name
Substitute to a number!

8. Try & Error
virsh memtune virtual_machine --hard-limit size
It is wrong!!
It should be:

9. Using systemd
Using echo command to change /sys settings will be lost after reboot!
Solutions:
• Put the commands into /etc/rc.local
OR
• Create a systemd script :
vi /etc/systemd/system/set_transparent_hugepages.service
[Unit]
Description=Disable transparent hugepages
After=multi-user.target
[Service]
ExecStart=/usr/bin/bash -c 'echo never > /sys/kernel/mm/transparent_hugepage/enabled'
[Install]
WantedBy=graphical.target
systemctl enable set_transparent_hugepages.service

10. Vi/Vim Editing
It requires you using vi or vim!

11. Grub configuration
It’s talking about modifying kernel options in GRUB:
vi /etc/default/grub
GRUB_CMDLINE_LINUX=“… default_hugepagesz=1G hugepagesz=1G hugepages=4 hugepagesz=2M hugepages=1024"
grub2-mkconfig -o /boot/grub2/grub.cfg

12. Using yum
yum list '*numa*'
yum install numactl
Command not found!!
You must install it first:

13. Using locate
It doesn’t show you the full path!
You have to find it out:

14. Many more…

15. Thank you!