RAID
It is difficult to move RAID to a new system. With a single disk, it is relatively easy to move the disk to a new system. It can simply be connected to the new system, if it has the same interface available. However, this is not so easy with a RAID array. There is a certain kind of Metadata that says how the RAID is set up. A RAID BIOS must be able to read this metadata so that it can successfully construct the array and make it accessible to an operating system. Since RAID controller makers use different formats for their metadata (even controllers of different families from the same manufacturer may use incompatible metadata formats) it is almost impossible to move a RAID array to a different controller. When moving a RAID array to a new system, plans should be made to move the controller as well. With the popularity of motherboard integrated RAID controllers, this is extremely difficult. Generally, it is possible to move the RAID array members and controllers together. Software RAID in Linux and Windows Server Products can also work around this limitation, but software RAID has others (mostly performance related).