Chapter Four
RAID controller configuration
Controller Description
The VOYAGER 3000 is a SCSI to SCSI RAID controller specifically designed to provide RAID 0, 1, 0+1, 3 or 5 capability to any host system equipped with a SCSI interface. It is totally independent of the host system's operating system with all the RAID functions performed by the controller hardware. In effect, it endows the host system with the high speed and fault-tolerant disk storage operation of RAID technology. The VOYAGER 3000 has comprehensive drive failure management that allows automatic reassignment to reserve blocks when a bad sector is encountered during a write. Hot-swapping is supported through automatic disconnection of a failed drive and detection of a fresh drive followed with background rebuilding of the data. The controller also supports spare drive operation. All these failure recovery procedures are transparent to the host system.
The controller is housed in a removable device canister which allows for minimum Mean Time to Repair (MTTR) periods. It is configured as one host bus with up to two target buses of 3-7 drives on each bus.
Figure 4-1 Front view of controller (within a canister)
The controller hardware is pre-configured when it leaves the factory but it is the responsibility of the user to configure the logical volumes according to the capacities and RAID levels.
Controller Configuration
This section covers configuration issues involved with the RAID system. Figure 4-2 shows a logical view of a Voyager 3001 configuration. In this case there are three SCSI buses connected to the controller across the three channels. Channel 2 makes up the host SCSI bus with channels 0 and 1 making up the target buses.
