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=Introduction=
There are several reasons why one would want a [http://en.wikipedia.org/wiki/RAID#RAID_5 RAID 5] configuration for your Amahi server if one has the money to buy at least 3 drives needed. The main reasons, however, are performance and redundancy. A RAID 5 array splits up a given file and its parity and distributes it across all the disks. The bad news is that if one has N disks, each with capacity C, the total array capacity is (N - 1) * C - one disk is lost to parity. On the other hand, a RAID 5 array has almost RAID 0 performance, and can survive the loss of one disk without loss of data. One thing that must be kept in mind with any RAID array (and one thing I didn't know about until it happened to me) is that RAID arrays are susceptible to data loss if not shut down correctly. A sudden power outage can result in data loss, so if a RAID array is used, it is important to use a [http://en.wikipedia.org/wiki/Uninterruptible_power_supply UPS].
Note: Depending on what you want to use your RAID 5 array for, you might want to consider using Greyhole over RAID 5. For some details about advantages and disadvantages of Greyhole vs RAID 5, see the [http://code.google.com/p/greyhole/#Greyhole_is_like_RAID-5,_but_better Greyhole project page].
Greyhole has been [[Greyhole|integrated in Amahi]] since version 5.3.
This wiki entry is for the installation of a software RAID 5 array using 3 disks that are the same size, 2 TB. At the end, the RAID array will be used to host all the shares on the server. My server has a separate hard drive on which I installed Fedora 12 and the Amahi software. The Amahi software should be installed and working correctly before the RAID array is created. Technically, it doesn't matter that Amahi is running first, but it makes it slightly easier to set up.
