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Creating RAID systems with Raider

Parachute

Article from ADMIN 12/2012

By Oliver Frommel

Along with regular backups, a RAID system should be a matter of course in any good server. This workshop shows how to convert an existing Linux installation to a RAID system and avoid the pitfalls on the way.

If you are looking for more performance or more security, RAID storage is always a useful solution. Whereas the non-redundant RAID 0 speeds up data access, RAID 1 duplicates your data and therefore gives you more resilience. The combination of the two is called RAID level 10, which offers the user the best of mirroring and striping. Creating a RAID system on two partitions of a hard disk makes little sense because, if the disk fails, both "disks" in your RAID are goners. However, you can create multiple partitions on a hard disk and assign them to different RAID arrays. I'll provide an example later in the article.

If you are installing a new Linux system, you can create a RAID system during the installation process, provided the system has enough hard drives. For example, with Red Hat or CentOS, during the installation you would first select Basic Storage Devices and then in a subsequent step Create Custom Layout . When you create a new partition, instead of choosing a filesystem, select Create Software RAID. After creating at least two RAID partitions, the installer gives you a RAID device option, where you can select the partitions you just created. The installer checks for the minimum number of partitions and refuses, for example, to create a RAID 6 with only two RAID partitions.

However, what do you do if the machine has already been used for a length of time with a simple filesystem? In principle, it is not difficult to build a RAID manually from a conventional filesystem, but there are some things to note. A script by the name of Raider makes the process easier by converting a simple Linux installation to RAID. It checks the prerequisites, copies the data, sets up a new RAID, and binds all necessary partitions.

After downloading and unpacking the Raider package from the website [1], you'll need a few other items before you can install Raider: It depends

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