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RHEL -7 Notes

study notes 2

— command line file

1, create and delete files

Create a file touch xxxx

touch -t 20151225 create a file and specify time properties

rm xxx delete the file

rm -rf forced to delete files

2. Create a directory and delete the directory

mkdir -p xxx/yyy recursively create directories;

rmdir xxx delete […]

How to Set up Nginx High Availability with Pacemaker and Corosync on CentOS 7

How to Set up Nginx High Availability with Pacemaker and Corosync on CentOS 7

We will create the Active-Passive Cluster or Failover-cluster Nginx web server using Pacemaker on a CentOS 7 system. Pacemaker is an open source cluster manager software that achieves maximum high availability of your services. It’s an advanced and scalable HA cluster […]

Install Gnome GUI on CentOS 7 / RHEL 7

Install Gnome GUI on CentOS 7 / RHEL 7

Linux admins spend most of their time on working in a terminal; there are some who like to work on GUI instead of a terminal. By default, CentOS 7 installed as the minimal server, and user intervention is required to change the installation type. This […]

Performance Co-Pilot (PCP) on my RHEL server to capture performance logs

# run these commands on a Centos 7 server as root yum install -y pcp pcp-webapi pcp-system-tools chkconfig pmcd on service pmcd start chkconfig pmlogger on service pmlogger start chkconfig pmwebd on service pmwebd start # open port 44323 in the firewall # To start vector on your laptop docker run -d –name vector […]

ps command #1 – Basic

A linux command to monitor the system process consuming resources on the server. If you are working on a linux system it is good to have at least basic understanding of this command.

ps program or command when run take a snapshot of running processes at that time and display on the terminal which can […]

memory usage in Linux per process

Not because I really want to; but because I just don’t have the money to spend on a 2+ GB RAM VPS and I would like to run Jira.

In order to do this I keep a close eye on the processes running and how much memory each takes.

For this I found […]

Top Show Running Processes

he Linux top command is used to show all the running processes within your Linux environment. This guide shows you how to use the top command by explaining the different switches available and the information that is displayed:

How To Run The Top Command

In its basic form all you need to do to show […]

Linux memory management

I think that is a common question for every Linux user soon or later in their career of desktop or server administrator “Why Linux uses all my Ram while not doing much ?”. To this one today I’ve add another question that I’m sure is common for many Linux system administrator “Why the command […]

XFS Filesystem has duplicate UUID problem

If you can not mount your XFS partition with classical wrong fs type, bad superblock etc. error and you see a message in kernel logs (dmesg) like that:

XFS: Filesystem sdb7 has duplicate UUID – can’t mount

you can still mount the filesystem with nouuid options as below:

mount -o nouuid /dev/sdb7 disk-7

But every […]

CentOS 7 through nmcli team to achieve multiple network card binding

CentOS 7 through nmcli team to achieve multiple network card binding

nmcli con add type team con-name team0 ifname team0 config ‘{“runner”:{“name”:”roundrobin”}}’

Run ip link command to view the interface available in the system 1, create a bond card nmcli con add type team con-name team0 ifname team0 config ‘{ “runner”: { “name”: “roundrobin”}}’ various […]