Windows storage: disks, volumes, Storage Spaces and RAID

1. Disks and volumes #

Preparing a disk.

Initialize, partition, format #

A new disk is initialized as GPT (recommended, required beyond 2 TB and for UEFI) or MBR (legacy). Partitions are created, formatted with a file system and mounted on a letter or folder.

Get-Disk | Format-Table Number, FriendlyName, Size, PartitionStyle, OperationalStatus
Initialize-Disk -Number 1 -PartitionStyle GPT
New-Partition -DiskNumber 1 -UseMaximumSize -DriveLetter D |
    Format-Volume -FileSystem NTFS -NewFileSystemLabel Data -AllocationUnitSize 4096 -Confirm:$false
Get-Volume ; Get-PSDrive -PSProvider FileSystem
Resize-Partition -DriveLetter D -Size (Get-PartitionSupportedSize -DriveLetter D).SizeMax   # étendre après agrandissement du disque

diskpart
DISKPART> list disk
DISKPART> select disk 1
DISKPART> clean                 # efface la table de partitions : vérifiez le numéro !
DISKPART> convert gpt
DISKPART> create partition primary
DISKPART> format fs=ntfs quick label=Data
DISKPART> assign letter=D

Common mistake: Running clean or Clear-Disk on the wrong disk. Check the number with Get-Disk (size, model, serial number) right before; a system or data disk is not recoverable afterwards.

NTFS or ReFS? #

2. Redundancy: Storage Spaces and RAID #

Protecting data against a disk failure.

Storage Spaces #

Storage Spaces is Windows’ modern software RAID. Disks form a pool; virtual disks are created in it with a chosen resiliency. The old “dynamic disks” (mirror, RAID 5 in Disk Management) are deprecated in favor of Storage Spaces.

Get-PhysicalDisk -CanPool $true
New-StoragePool -FriendlyName Pool1 -StorageSubSystemFriendlyName 'Windows Storage*' -PhysicalDisks (Get-PhysicalDisk -CanPool $true)
New-VirtualDisk -StoragePoolFriendlyName Pool1 -FriendlyName Miroir -ResiliencySettingName Mirror -NumberOfDataCopies 2 -UseMaximumSize -ProvisioningType Fixed
Get-VirtualDisk Miroir | Get-Disk | Initialize-Disk -PartitionStyle GPT -PassThru |
    New-Partition -UseMaximumSize -DriveLetter E | Format-Volume -FileSystem ReFS -NewFileSystemLabel Miroir
Get-StoragePool Pool1 | Get-PhysicalDisk | Select-Object FriendlyName, HealthStatus, Usage
Repair-VirtualDisk -FriendlyName Miroir             # après remplacement d'un disque

Good to know: Parity has heavy write penalties: keep it for archives and backups, and use mirror for virtual machines and databases. RAID level principles are detailed in the Linux course. Storage Spaces Direct (Datacenter edition) extends this model to several clustered servers (hyperconvergence).

Hardware RAID #

A hardware RAID controller presents Windows a single, already redundant disk; it is managed with the vendor’s tool (iDRAC, iLO, MegaRAID). Do not combine hardware RAID and Storage Spaces on the same disks: Storage Spaces wants disks presented as is (HBA or JBOD mode).

3. Protecting and optimizing data #

Snapshots, quotas, deduplication.

Shadow copies, quotas and deduplication #

# Clichés instantanés (VSS) : versions précédentes des fichiers d'un partage
vssadmin add shadowstorage /for=D: /on=D: /maxsize=10%
vssadmin create shadow /for=D:          # sur un serveur ; planifiez-les deux fois par jour
vssadmin list shadows

# Quotas et filtrage de fichiers (rôle FSRM)
Install-WindowsFeature FS-Resource-Manager -IncludeManagementTools
New-FsrmQuota -Path D:\Data\Users -Size 20GB -Description 'Dossiers personnels'

# Déduplication des données (fichiers, VDI, sauvegardes)
Install-WindowsFeature FS-Data-Deduplication
Enable-DedupVolume -Volume D: -UsageType Default ; Get-DedupStatus

Common mistake: Treating shadow copies or RAID as a backup. They are on the same server, often on the same volume: ransomware, a controller failure or a fire takes them away. See backup, Hyper-V and troubleshooting.

Commands to know #