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How to replace a Volume in mdadm software RAID array

replace a Volume in mdadm software RAID array
mdadm, which is a Linux Software RAID, is not inferior to a typical hardware RAID controller, and just like a hardware controller – enables us to swap physical disks inside the RAID array. It requires executing some commands indeed, but the whole process still seems to be pretty straightforward.

Usually, we replace a disk in RAID when it starts failing, but there might be scenarios, where you just want to swap mechanical SATA disks in RAID with SSDs, one by one, for better performance, without reinstalling the whole OS.
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Debian Installation with LVM RAID 1 and Hot Spare

Debian 11 installation
Debian is a powerful, multipurpose, and super stable Linux distro, however, in my humble opinion, its installation wizard was never a strong point of this Linux distribution, making it pretty difficult to install for beginners. While the standard setup with just a single disk is still relatively digestible for most users, the more sophisticated setup involving RAID with LVM might be pretty hard and arduous. The purpose of this tutorial is to help you go through the whole installation procedure smoothly and painlessly.

In this tutorial, I present Debian 11 (Bullseye) installation based on MD-RAID, configured in Mirroring mode, with an additional Hot Spare drive and LVM partitioning on top of it.
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Comment uncomment and replace characters in multiple lines in Vim

Modifying files in Vim can be arduous and time-consuming, especially when we want to modify multiple lines at once. The typical use case is modifying a configuration file in the system when it is required to comment or uncomment multiple lines at a time, or to replace the same character in many similar lines from the top to the bottom. Here are a few hints on how to facilitate multiple line modifications in text files using Vim editor.

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Resize Cinder based Volume attached to an Instance in OpenStack

OpenStack Instance volume resize
One of the key features in OpenStack is the ability to resize the Instance’s flavor to increase resource limits used by Instances, such as vCPUs and RAM. Unfortunately, in the case of an Instance with a Cinder-backed volume, changing flavor does not affect the underlying volume.
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How To Enable LLDP Service on CentOS

linux networking
LLDP (Link Layer Discovery Protocol) can be essential in situations of complex network-server infrastructure configurations and it’s extremely helpful in case there is no direct access to our setup but we need to determine what network ports on the switches are our servers NIC cards connected to.

Below we present how to install and enable LLDP Daemon on CentOS Linux, based on CinderCloud VPS, and check what are the corresponding neighbor port IDs connected to our server network cards.
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