Disk Space Allocation Question

Best Practice for Allocating Space on a Large RAID Array​

1. Single Large Volume, Multiple Shares (Folders)​

• Most flexible for growth: You allocate the entire 72 TB as a single volume (e.g., D, then create folders like D:\Movies, D:\KidsMovies, etc., and share each folder individually via SMB.
• Easier management: Expanding a share’s storage needs is as easy as moving files—no volume resizing or extending partitions.
• Windows Server Backup Limitation: The built-in Windows Server Backup tool won’t back up more than 15 TB per volume. However, this typically matters only for data/volumes you absolutely need to back up using that tool (which for large, static media collections, you might not). For critical/smaller shares you want absolute backup assurance, keep them under 15TB.
• File system features: NTFS/Refs features like deduplication, quotas, file screening, etc., remain available and easy to apply per share/folder.

2. Multiple Smaller Volumes (Each Share = New Volume)​

• Backup flexibility: Lets you use built-in Windows Server Backup to protect specific volumes under 15 TB.
• Complexity: Managing multiple volumes increases administrative overhead. Extending volumes after they fill up can lead to fragmentation and non-contiguous disk spaces, as you’ve already experienced.
• Wasted space risk: If some shares grow faster than others, you might run into some volumes being nearly full and others sitting half-empty, unless you continually rebalance.

Real-World Recommendations​

• Go with Option 1: One large NTFS/ReFS volume, individual folder shares.
  • This is the best choice for almost everyone nowadays, especially with very large RAID arrays.
  • Leverage server-side features for quotas, reporting, and permissions on folders rather than volumes.
  • Use third-party backup software for large-volume backup scenarios, or manually sync/back up only the folders you care about.
• Exception: If you have a subset of highly critical data you want backed up with the built-in tool AND under 15 TB, create a small, dedicated volume for just that data.
  Keep the big media stuff on the giant volume.

Additional Tips​

• File System: Use ReFS for large pools where possible (for media, it gives better data integrity), but NTFS is totally fine and better supported for most FS-level features.
• Deduplication: If you have lots of redundant media files across folders, enable Windows Deduplication to reclaim space.
• Quotas/Screening: Use Windows File Server Resource Manager (FSRM) for folder quotas and file type restrictions if needed.

Summary Table​