RAID Storage Array

Overview

A RAID storage array is a chassis full of disks that presents itself to servers as fast, fault-tolerant capacity. RAID, a redundant array of independent disks, spreads data across many drives so that one or more can fail without losing anything, and so that reads and writes hit several spindles at once. The array packages that idea with the redundancy and hot-swap serviceability expected of shared storage that many hosts depend on.

The box is built on a Chassis & Rails of hot-swap bays feeding a SAS/SATA Backplane, populated with Hard Disk Drive units for capacity and Solid-State Drive units for speed. Two RAID Controller canisters run the array in active-active redundancy, exposing storage through Host Port connections and chaining extra shelves through Expansion Port links. Dual Power Supply modules, hot-swap Blower Motor fans, and a LCD Status Panel round it out so nothing about the array is a single point of failure.

How it works

Each drive plugs into the midplane, which carries two SAS expanders so both controllers can reach every disk. A controller's RAID-on-chip processor turns each incoming write into a stripe across several drives plus parity, so the data can be rebuilt if a drive dies; the spare then backfills automatically. Recent writes are held in Cache DRAM and acknowledged immediately for speed, while a Cache Backup Unit unit guarantees those writes survive: on power loss its battery flushes the cache to flash before the lights go out.

Because the two RAID Controller canisters mirror each other's state, a host keeps its connection through the survivor if one controller fails or is pulled for service. The LCD Status Panel surfaces capacity, rebuild progress, and faults at the rack, while the redundant fans and supplies make routine replacement a hot-swap rather than a shutdown.