Howto migrate a single disk Linux installation to mdadm raid with luks encryption and LVM volumes with minimum downtime in 11 Steps

This document describes howto migrate a single disk linux installation used for virtualization with kvm to a RAID 5 array. In this setup, 2 disks are added. Including the original disk a 3 disk RAID 5 is created. It is sought out to do the complete migration causing only one reboot downtime. During the process of syncing the virtual machine data, the guests can experience losses in disk performance.

Overview: Current and target partitioning layout
This manual is using mdadm to create software RAID. It can be adapted to any RAID level that can support one disk missing. The setup used as in this example is a CentOS 6.5 installation, partitioned as following described: […]

By |May 16th, 2014|Linux distributions|Comments Off on Howto migrate a single disk Linux installation to mdadm raid with luks encryption and LVM volumes with minimum downtime in 11 Steps

Installing and managing .rpm packages on CentOS 6.5

It is possible to organise .rpm package files, for example downloaded by hand (or wget), in a way that lets you use them as a repository for the yum tool. This way you can have your own local yum repository of .rpm files.
# mkdir local-repo
# mv gdisk-0.8.7-125.1.i686.rpm local-repo/
# yum install createrepo
# […]

By |May 5th, 2014|Linux distributions|Comments Off on Installing and managing .rpm packages on CentOS 6.5

changing or adding cryptsetup LUKS password or keyfile

Devices encrypted with luks support more than one passphrase. Here an example with a normal 5MB file. Just replace the “crypt_file.img” with /dev/sdX or whatever device you have encrypted.

user@host:~$ dd if=/dev/urandom bs=5M count=1 of=crypt_file.img
1+0 records in
1+0 records out
5242880 bytes (5.2 MB) copied, 0.507585 s, 10.3 MB/s

sudo cryptsetup luksFormat crypt_file.img
WARNING!
========
This will overwrite data on crypt_file.img irrevocably.

Are […]

By |December 18th, 2012|Hardware, Linux distributions|Comments Off on changing or adding cryptsetup LUKS password or keyfile

cloning debian / ubuntu apt packages to new hardware installation

Using the following method to clone all installed packages to a new installation requires the new operating system to be the same as the original (as in debian 7 => debian 7). Apt-clone will also copy the /etc/apt/sources.list. If you did install software via for example dpkg -i skype_0.8.15.deb, the switch –with-dpkg-repack will try to […]

By |November 12th, 2012|Linux distributions|2 Comments