Choosing the correct hardware is as important as choosing the correct volume manager. To start with, all disks used for the system should be of identical geometry. This prevents wasting disk space and facilitates the creation of the mirror, the contingency disk, and the hot spare disk. Further, to ensure maximum system availability, connect all disks to different host bus adapters (HBAs). If this is not possible, ensure that at least two HBAs are available, and that the system disk and its mirror are on different HBAs. Finally, if possible, ensure that HBAs are on different I/O boards to avoid a single point of failure within the server.
IDE, SCSI, or FC-AL drives can be used. For IDE drives, ensure that an IDE master is not mirrored to an IDE slave, as loss of the master means loss of access to the slave. We do not recommend that you use LUNs on a hardware RAID controller because this introduces extra components (and therefore, possible points of failure) to the boot path.