Server Hardware & RAID Explained Before Installing Windows Server

Decide the Roles Before You Touch the Hardware

Hardware questions have no answer until the role question is answered. A domain controller is a light job — it answers logon and DNS requests and sips resources. A file server cares about disk and network, not CPU. A Hyper-V host is the sum of every virtual machine it will carry, plus something for itself. A database server eats memory and disk speed all day.

Write the roles down as a list, including the ones planned for next year. Almost every undersized server in a small office was bought for the roles of the day it was ordered — and the list also decides everything that follows: RAID 10 earns its cost under a database, and is a luxury under a plain file share.

Choose the RAID Level for the Job, Not by Habit

RAID joins several physical drives into one logical drive that Windows sees. The levels differ in what you trade — space, speed or safety:

RAID 0 stripes data across drives for speed and gives zero protection — one dead drive takes everything, so it has no place under server data. RAID 1 mirrors two drives: half the space, simple, and the rebuild is a quick straight copy — the standard home for the operating-system volume. RAID 5 spreads data plus parity across three or more drives and survives one failure, but its rebuild on today's very large drives is a long, risky window. RAID 6 adds a second parity and survives two failures, which makes rebuilds far calmer with big drives. RAID 10 mirrors pairs and stripes across them: half the space, the best speed, and the safest rebuild.

Do the Capacity Maths Before You Buy

The same drives give very different usable space depending on the level — run the numbers on paper before ordering, using the worked examples from the video:

RAID 5 keeps the most space of the protected levels but survives only one failure; RAID 6 and RAID 10 give up more space — RAID 6 for a second parity, RAID 10 for mirrors — and survive their failures far more calmly.

Pick a Real RAID Controller

The controller is the part that runs the array, and it belongs on the decision list before the install, not after. A dedicated hardware RAID controller with its own cache manages the array independently of Windows, keeps performance steady, and reports drive health properly. Letting the operating system or a cheap onboard chip run an important array means the array's safety depends on the very system it is supposed to protect.

Use Server-Grade Drives, Not Desktop Drives

A server runs 24x7, and its drives should be rated for exactly that. Enterprise and NAS-grade drives are built for continuous duty, for vibration from neighbouring drives, and for being part of an array — desktop drives are built for a PC that sleeps at night, and in a busy array they can drop out or fail early in ways that look like random corruption. Keep every drive in an array the same model and size, so performance is even and a spare always fits.

Do Not Skip ECC Memory

ECC (Error-Correcting Code) memory detects and fixes single-bit memory errors silently, before they can corrupt data or crash the server. Ordinary desktop RAM cannot do this — a flipped bit just flows through. On a machine whose whole job is to hold other people's data and logons, that quiet correction is one of the real differences between a server and a desktop in a bigger box, and it is decided when the hardware is bought, not when Windows is installed.

Write the Disk Layout on Paper

The last pre-install decision is the cheapest and the most skipped: the disk layout. Design it in order — first which drives form which array at which RAID level, then which volumes each array becomes and how big each one is, and only then the drive letters and share names. Give the operating system its own volume with generous room for years of updates, and keep user data and virtual machines on their own volumes, so Windows can one day be rebuilt without touching the data beside it.

Remember: RAID Is Not a Backup

Decide the backup target at the same time as the RAID level, write it on the same sheet of paper, and never let the backup live on the array it is protecting.