The amount of NAS storage you need depends on what you are storing, how many people will use it, and how much your data will grow over the next 3-5 years. Home NAS capacity requirements vary substantially; calculate them from current data, expected growth and the chosen RAID configuration. Small-business requirements vary substantially with staff count, workload, retention, backups and surveillance use, so they should be measured individually. This guide walks through exactly how to calculate your requirements and choose the right NAS configuration for your situation in Australia.
In short: A 2-bay NAS with 2 x 4 TB drives in RAID 1 gives roughly 4 TB usable. Enough for most individuals. A 4-bay NAS with 4 x 8 TB drives in RAID 5 gives roughly 24 TB usable. Enough for most small businesses and power users. Always plan for 3-5 years of growth and remember that RAID reduces your raw capacity by 25-50% depending on the level you choose.
Why Capacity Planning Matters Before You Buy
A NAS is not like a USB drive you can swap out when it fills up. Once you commit to a NAS enclosure with a specific number of bays and populate it with drives, your expansion options are limited. You can upgrade to larger drives over time, but A NAS cannot gain additional internal bays, although some specific models support compatible external expansion enclosures. Buying the wrong size means either wasting money on capacity you never touch or facing an expensive replacement sooner than expected.
The other factor most buyers underestimate is RAID overhead. If you buy 4 x 8 TB drives (32 TB raw), you do not get 32 TB of usable storage. Depending on your RAID configuration, you might get as little as 16 TB usable. Understanding this before you buy prevents the unpleasant surprise of plugging in your new NAS and finding half the capacity you expected.
Step 1. Calculate Your Current Data
Start with what you have right now. Add up the storage consumed across all the devices and services you plan to consolidate onto your NAS. Be thorough. The most common planning error is forgetting entire categories of data.
Home User Data Audit
Check each of these sources and note how much space they use:
- Photos: Check your phone storage, iCloud/Google Photos usage, and any photos on your computer. Measure the household’s existing photo library directly, as storage varies with image count, format, resolution and retention. If you shoot RAW or use a mirrorless camera, this could be 1-5 TB. See our photography NAS guide for detailed calculations.
- Videos: Home videos, drone footage, GoPro clips. 4K video storage varies widely with codec, bitrate and frame rate; inspect representative files from the devices and settings you use. A family with a few years of video might have 200 GB-2 TB.
- Music: If you have a local music library, expect 5-50 GB depending on format and collection size. Most streaming-only users can skip this.
- Documents: Word files, PDFs, spreadsheets. Usually under 10 GB unless you are archiving scanned documents.
- Computer backups: Full system backups for each PC or Mac. Budget 200-500 GB per computer if using Time Machine or similar.
- Cloud replacement: If you are moving off iCloud or Google Drive, include whatever you currently store there.
Small Business Data Audit
Business data tends to be larger and grows faster than personal data. Audit these categories:
- Shared files and documents: Company documents, project files, accounting data. Measure the existing shared-file dataset; office storage varies with workload, file types, retention and versioning.
- Email archives: If you back up or archive email locally. Budget 2-10 GB per user depending on retention period.
- Workstation backups: Full image backups of staff computers. Budget 300-500 GB per workstation.
- Server backups: If backing up a Windows Server or other on-premises server to the NAS. Could be 500 GB-5 TB depending on the server.
- Surveillance footage: If using the NAS for IP camera recording, this is often the largest single consumer of storage. Continuous camera storage depends on configured bitrate, codec, frame rate and scene complexity; calculate it from the actual camera stream settings.
- Databases and applications: Line-of-business applications, CRM data, design files. Varies enormously. Measure what you have.
Tip: On Windows, right-click your user folders and check Properties. On macOS, use About This Mac > Storage. On iCloud or Google Drive, check your storage management page. Write down every number. The total is your current data footprint.
Step 2. Estimate Future Growth
Your NAS should last 3-5 years before you consider replacing it. That means your storage needs to cover not just what you have today, but what you will accumulate over that period. The following are illustrative planning assumptions, not measured averages; replace them with growth calculated from your own historical data where possible:
| Use Case | Typical Annual Growth | 3-Year Projection |
|---|---|---|
| Individual photos and documents | 50-200 GB/year | 150-600 GB |
| Family with kids (photos, video, backups) | 200-500 GB/year | 600 GB-1.5 TB |
| Photography enthusiast (RAW files) | 500 GB-2 TB/year | 1.5-6 TB |
| Video creator or editor | 2-10 TB/year | 6-30 TB |
| Small office (5-10 staff) | 500 GB-2 TB/year | 1.5-6 TB |
| Small business with surveillance | 5-20 TB/year | 15-60 TB |
| Plex or media server | 1-5 TB/year | 3-15 TB |
The general rule: take your current data, add your estimated 3-year growth, then add a 20% buffer on top. That is your target usable capacity. If you are unsure, round up to the next drive size. It is always cheaper to buy a bit more now than to replace drives or the entire NAS in 18 months.
Step 3. Understand RAID Overhead
RAID is the system your NAS uses to protect your data against drive failure. It works by spreading data across multiple drives with varying levels of redundancy. The trade-off is that some of your raw storage capacity is used for this protection. If you are unfamiliar with RAID levels, our complete RAID guide explains each one in detail. Here is the practical impact on usable storage:
| RAID Level | Minimum Drives | Usable Capacity (with identical drives) | Drive Failures Tolerated |
|---|---|---|---|
| RAID 0 | 2 | 100% of raw (no protection) | 0. any failure loses all data |
| RAID 1 | 2 | 50% of raw | 1 drive |
| RAID 5 | 3 | ~67-75% of raw (n−1 drives) | 1 drive |
| RAID 6 | 4 | ~50-67% of raw (n−2 drives) | 2 drives |
| RAID 10 | 4 | 50% of raw | 1 drive per mirror pair |
| SHR (Synology) | 2+ | Similar to RAID 5/6 but allows mixed drive sizes | 1 or 2 drives (SHR-2) |
RAID Capacity Examples with Real Drive Sizes
To make this concrete, here is what you actually get with common NAS configurations using drives available in Australia:
| Configuration | Raw Capacity | RAID Level | Usable Capacity (approx.) |
|---|---|---|---|
| 2 x 4 TB (2-bay NAS) | 8 TB | RAID 1 / SHR | 4 TB |
| 2 x 8 TB (2-bay NAS) | 16 TB | RAID 1 / SHR | 8 TB |
| 2 x 16 TB (2-bay NAS) | 32 TB | RAID 1 / SHR | 16 TB |
| 4 x 4 TB (4-bay NAS) | 16 TB | RAID 5 / SHR | 12 TB |
| 4 x 8 TB (4-bay NAS) | 32 TB | RAID 5 / SHR | 24 TB |
| 4 x 16 TB (4-bay NAS) | 64 TB | RAID 5 / SHR | 48 TB |
| 4 x 8 TB (4-bay NAS) | 32 TB | RAID 6 / SHR-2 | 16 TB |
| 4 x 16 TB (4-bay NAS) | 64 TB | RAID 6 / SHR-2 | 32 TB |
Important: Drive manufacturers use decimal gigabytes (1 TB = 1,000,000,000,000 bytes) while operating systems report in binary gibibytes. A drive labelled 8 TB will show as roughly 7.27 TB in your NAS. Factor in an additional 7-10% reduction from what is listed above.
Step 4. Choose the Right Number of Bays
The number of bays in your NAS determines both your maximum capacity and your RAID options. This is the one thing you cannot change later without replacing the entire unit, so it is worth getting right.
2-Bay NAS
Best for individuals and couples with moderate storage needs. With RAID 1 (mirroring), a 2-bay NAS gives you the capacity of one drive with full redundancy. Maximum usable capacity depends on the largest drives supported by the specific NAS model; NAS-rated drives above 24 TB now exist, but compatibility must be verified. Suitable for personal photos, documents, computer backups, and light Plex streaming. Models like the Synology DS225+ are popular entry points in Australia.
4-Bay NAS
The most versatile option and the sweet spot for most buyers. A 4-bay NAS supports RAID 5 (one drive of redundancy) or RAID 6 (two drives of redundancy), giving you a strong balance of capacity and protection. Maximum usable capacity in RAID 5 with 24 TB drives: roughly 72 TB. This covers families with heavy media collections, prosumers, home lab enthusiasts running Docker containers, and small businesses with 5-15 staff. See our best 4-bay NAS roundup for specific models.
6-Bay and Above
Needed for video editors working with 4K or higher footage, businesses with surveillance systems, or organisations that need 50+ TB of usable storage. 6-bay and 8-bay desktop models from Synology and QNAP offer substantial capacity without going to rackmount hardware. Tower NAS models with more than eight bays are available, alongside higher-bay-count rackmount systems.
Bay Count Decision Table
| Your Situation | Recommended Bays | Why |
|---|---|---|
| Individual user, light storage (photos, docs, backups) | 2-bay | RAID 1 with 4-16 TB usable is more than enough |
| Family or household (multiple devices, Plex, backups) | 4-bay | RAID 5 with 12-48 TB usable covers most families for 5+ years |
| Home lab, photography, content creation | 4-bay (or 6-bay if shooting video) | More bays allow RAID 5/6 with room to grow |
| Small business (5-20 staff, shared files, backups) | 4-bay or 6-bay | RAID 5 or RAID 6 depending on data criticality |
| Business with surveillance | 6-bay or 8-bay | Surveillance footage consumes storage rapidly |
| Video production, large media library | 6-bay to 8-bay | 4K and higher video demands significant capacity and throughput |
Step 5. Pick the Right Drive Size
NAS-grade drive capacities now extend beyond 24 TB, although Australian availability and NAS-model compatibility vary. Compare current per-terabyte pricing across compatible drive capacities; the best-value capacity changes with model, retailer and stock levels. For a detailed comparison of the leading NAS drive brands, see our NAS hard drive guide and our Seagate IronWolf vs WD Red comparison.
Key considerations when choosing drive size:
- Cost per terabyte: Larger drives cost more in total but less per terabyte. An 8 TB drive is significantly cheaper per-TB than a 4 TB drive. However, the jump from 16 TB to 20 TB or 24 TB brings diminishing returns. The premium per-TB increases at the top end.
- RAID efficiency: Larger drives mean more usable capacity from fewer bays. A 4-bay NAS with 16 TB drives in RAID 5 gives 48 TB usable. Matching 48 TB usable with 8 TB drives in RAID 5 requires seven drives.
- Rebuild time: Larger drives take longer to rebuild if one fails. Large-drive RAID rebuilds can be lengthy, with duration varying by NAS hardware, drive performance, array layout, workload and drive condition; RAID 5 remains without protection from a second drive failure during the rebuild. For drives 12 TB and above, consider RAID 6 or SHR-2 for the extra redundancy.
- Availability: NAS-grade drive prices have risen significantly from early 2025 levels. Drives that were comfortably under $160 for 4 TB are now consistently above $200. Stock levels fluctuate. Check availability at retailers like Scorptec, PLE, and Mwave before committing to a specific drive size.
Tip: You do not have to fill all bays on day one. Buy a 4-bay NAS but start with 2 or 3 drives, leaving empty bays for future expansion. Supported Synology and QNAP configurations can add drives without deleting existing data, but eligibility depends on the NAS model, operating system, RAID type and current array layout; verify the vendor procedure first and maintain a backup. This spreads the cost while giving you room to grow.
Capacity Planning by Use Case
Rather than guessing, here are specific recommendations based on real-world Australian use cases. These account for RAID overhead, 3-year growth, and a 20% buffer.
Personal Backup and File Storage
You want to back up your phone photos, store documents, and have Time Machine or Windows backup running. Total data today is under 2 TB and growing slowly.
Recommended configuration: 2-bay NAS with 2 x 4 TB drives in RAID 1. Usable capacity: approximately 4 TB. This gives you room for a couple of years of growth. When you outgrow 4 TB, swap the drives for 8 TB or 16 TB models. A budget 2-bay NAS from Synology or Asustor handles this comfortably.
Family or Household
Multiple family members storing photos and videos, replacing iCloud or Google Photos, backing up several computers, possibly running Plex for the household. Total data today is 2-8 TB and growing at 500 GB-1 TB per year.
Recommended configuration: 4-bay NAS with 4 x 8 TB drives in RAID 5 or SHR. Usable capacity: approximately 24 TB. This handles current data plus 5+ years of family growth with comfortable headroom. A 4-bay home NAS like the Synology DS925+ or QNAP TS-464 suits this use case well.
Photography Enthusiast
Shooting RAW files, maintaining a large Lightroom catalogue, possibly backing up multiple external drives. Current library is 2-10 TB and growing at 1-2 TB per year.
Recommended configuration: 4-bay NAS with 4 x 16 TB drives in RAID 5 or SHR. Usable capacity: approximately 48 TB. This gives substantial room for large RAW collections and long-term growth. If data integrity is critical (it usually is for irreplaceable photos), consider RAID 6 or SHR-2 for dual-drive redundancy, which reduces usable capacity to approximately 32 TB but provides stronger protection.
Plex and Media Server
A personal media library of movies, TV shows, and music for streaming across the household and possibly remotely. Note that remote streaming via Plex relies on your internet upload speed. Current NBN upload rates depend on access technology, retail plan and provider: Home Fast II is offered at up to 50 Mbps upload on eligible FTTP/HFC services, while Home Fast I is up to 20 Mbps on FTTC and 5-20 Mbps on FTTN/FTTB. Plex stream capacity depends on measured upload speed and each file’s bitrate or transcode setting. CGNAT on some NBN connections can also block remote access entirely without a workaround.
Recommended configuration: 4-bay NAS with 4 x 8 TB (24 TB usable) for a moderate library, or 4 x 16 TB (48 TB usable) for large collections. RAID 5 or SHR is the standard choice. See our Plex NAS guide for model recommendations that include hardware transcoding.
Small Business (5-20 Staff)
Shared file storage, workstation backups, possibly a server backup target, and potentially centralised backup software like Synology Active Backup for Business or QNAP HBS. Total data today is 5-20 TB and growing at 1-3 TB per year.
Recommended configuration: 4-bay NAS with 4 x 16 TB drives in RAID 5 for approximately 48 TB usable, or a 6-bay NAS for more headroom. For business-critical data, RAID 6 is worth the capacity trade-off. A single drive failure during a RAID 5 rebuild can mean total data loss. Always implement a 3-2-1 backup strategy alongside the NAS.
RAID is not a backup. A NAS can be a backup destination, but data stored only on the NAS still needs an independent, preferably offsite or isolated, backup copy. RAID protects against drive failure, not against ransomware, accidental deletion, fire, theft, or NAS hardware failure. Every NAS deployment. Home or business. Should have at least one additional backup copy stored offsite or in the cloud. See our 3-2-1 backup guide for how to set this up properly.
Small Business with Surveillance
IP camera surveillance is one of the most storage-hungry NAS use cases. A single 4K camera recording continuously at medium quality uses roughly 40-60 GB per day. Four cameras running 24/7 can consume 5-7 TB per month. Motion-triggered recording can reduce storage use, but the reduction depends on scene activity, detection settings and pre/post-event recording intervals.
Recommended configuration: Dedicate a separate NAS (or separate volume) for surveillance. Retention depends on camera count, bitrate, codec, frame rate and recording schedule; calculate it from the planned camera-stream settings. For more than 8 cameras, look at 6-bay or 8-bay models. Synology Surveillance Station includes default device licences, while QNAP’s current QVR Surveillance includes free channels; additional cameras may require paid licences, so verify the entitlement for the selected model and software version. Factor this into your budget.
Video Editing and Content Creation
If you are editing 4K or higher video directly from a NAS, you need both capacity and throughput. A single hour of ProRes 4K footage is roughly 110-880 GB depending on codec and bitrate. Whether 1 GbE is sufficient depends on codec bitrate, stream count and whether proxy media is used; higher-bitrate or multi-stream workflows may require 2.5 GbE or 10 GbE. You need at least 2.5 GbE, ideally 10 GbE. See our networking guide for details on upgrading your connection speed.
Recommended configuration: 6-bay or 8-bay NAS with 16-24 TB drives in RAID 5 or RAID 6. QNAP models with Thunderbolt 4 connectivity (like the TVS series) allow direct high-speed connection to a Mac or PC without relying on Ethernet. A NAS with NVMe SSD cache also improves random read performance during editing workflows.
The Capacity Planning Formula
Here is the straightforward formula to determine how much usable storage you need:
- Current data: Total up everything you plan to store on the NAS.
- Growth projection: Multiply your estimated annual growth by 3 (for a 3-year NAS lifecycle) or 5 (for a 5-year lifecycle).
- Buffer: Add 20% to the combined total. Storage that is 90%+ full performs poorly and leaves no room for temporary files or unexpected needs.
- RAID adjustment: Divide your target usable capacity by the RAID efficiency factor to determine how much raw capacity you need to buy.
Example: You currently have 3 TB of data, growing at 1 TB per year, planning for 5 years.
- Current data: 3 TB
- 5-year growth: 5 TB
- Subtotal: 8 TB
- 20% buffer: 1.6 TB
- Target usable capacity: 9.6 TB (round to 10 TB)
- With RAID 5 on a 4-bay NAS (75% efficiency): you need roughly 13.3 TB raw, so 4 x 4 TB drives (16 TB raw, 12 TB usable) works perfectly.
Common Mistakes to Avoid
Buying Too Small to Save Money
A 2-bay NAS is cheaper than a 4-bay, and 4 TB drives are cheaper than 8 TB drives. But if you outgrow the NAS in two years, you are buying the whole thing again. NAS, drives, and the time to migrate your data. It is almost always cheaper to buy slightly more capacity than you think you need today. The price difference between two-bay and four-bay models varies substantially by product tier and retailer; compare current like-for-like models before deciding.
Ignoring RAID Overhead
Buyers who see "4 x 8 TB" and think they are getting 32 TB are setting themselves up for disappointment. In RAID 5, that configuration gives approximately 24 TB usable. In RAID 6, approximately 16 TB. In RAID 1, approximately 16 TB. Always calculate based on usable capacity after RAID, not raw drive totals.
Forgetting About Backups of the NAS Itself
If you plan to back up your NAS to the cloud or to an external USB drive, the backup destination needs to be at least as large as your NAS data. Cloud backup cost scales with stored volume and provider. For example, Backblaze B2 starts at US$6.95 per TB per month, so price a 10 TB NAS backup directly with the selected provider and include currency conversion and any retrieval charges. Factor this recurring cost into your budget alongside the upfront NAS and drive purchase.
Using Desktop Drives Instead of NAS Drives
Standard desktop hard drives (WD Blue, Seagate Barracuda) are not designed for the 24/7 operation and multi-drive vibration environment inside a NAS. NAS-rated drives like the Seagate IronWolf or WD Red series include firmware optimisations for RAID arrays, better vibration tolerance, and longer warranty periods (3 years standard, 5 years for Pro models). The price difference is worth it for a device that holds your important data.
Mixing Drive Sizes Without SHR
Traditional RAID levels (RAID 1, 5, 6) use the capacity of the smallest drive in the array for all drives. If you mix a 4 TB drive with three 8 TB drives in RAID 5, you get approximately 12 TB usable. Not the 20 TB you might expect. Synology's SHR (Synology Hybrid RAID) can use the extra space on larger drives, making mixed drive sizes practical. QNAP does not offer an equivalent. If using QNAP, stick to identical drive sizes for maximum efficiency.
Expansion Options If You Run Out of Space
If your NAS fills up, you have several options depending on your NAS brand and model:
- Replace drives with larger ones: Swap drives one at a time, letting the array rebuild between each swap. When all drives are replaced, expand the volume to use the new capacity. This works with both Synology SHR and traditional RAID on QNAP, though the process takes several days for large arrays.
- Add drives to empty bays: If you have unused bays, add new drives and expand the existing volume. This is why buying a 4-bay NAS and starting with 2-3 drives is a smart strategy.
- Add an expansion unit: Both Synology and QNAP sell expansion units (DX series for Synology, TR series for QNAP) that connect via USB or eSATA and add more bays to your existing NAS. These are useful but add complexity and a potential point of failure.
- Add a second NAS: For businesses that have outgrown a single unit, a second NAS can handle overflow or serve as a dedicated backup target. This also provides redundancy at the device level.
NBN Upload Speeds and Remote Access Considerations
If you plan to access your NAS remotely. For Plex streaming, offsite file access, or cloud sync. Your NBN upload speed becomes a limiting factor for capacity planning. Current upload rates depend on access technology, retail plan and provider: NBN lists Home Fast II at up to 50 Mbps upload on eligible FTTP/HFC services and Home Fast I at up to 20 Mbps on FTTC or 5-20 Mbps on FTTN/FTTB. This means transferring large files or streaming high-quality video remotely will be constrained regardless of how much storage you have.
CGNAT (Carrier-Grade NAT) on some NBN connections can also block inbound connections to your NAS entirely, preventing remote access without a VPN or relay service. Check with your ISP whether you are behind CGNAT before planning remote access workflows. See our remote access and VPN guide for solutions.
For cloud-based backup of your NAS, upload speed directly impacts how long your initial backup takes. Backing up 10 TB over a 20 Mbps upload connection takes roughly 46 days of continuous uploading. Plan accordingly. Your first cloud backup may take weeks, with incremental backups being manageable after that.
Cost Considerations in Australia
Storage planning is not just about capacity. It is about budget. Here is how costs break down for a typical NAS deployment in Australia in early 2026:
- NAS unit: A 2-bay NAS from Synology or QNAP starts at approximately $350-500 AUD. A 4-bay model runs $600-1,200 AUD depending on the CPU and RAM configuration. See our best NAS under $500 and best NAS under $1,000 guides for specific options.
- Hard drives: At the audit date, PLE listed Seagate IronWolf 4 TB, 8 TB and 16 TB drives at $369, $649 and $1,159 AUD respectively; recheck live retailer pricing immediately before publication. Prices have risen significantly since early 2025, and stock levels fluctuate. Shop around at Scorptec, PLE, Mwave, and Centre Com for the best current pricing.
- UPS (recommended): A basic UPS suitable for a NAS costs $150-300 AUD. This protects against power outages that can corrupt data mid-write. See our UPS guide.
- Cloud-backup cost depends primarily on stored volume, provider and retrieval policy; obtain a quote for the actual number of terabytes rather than using a flat annual allowance.
- Recalculate this example from live NAS, drive and UPS prices before publication; current drive prices alone can exceed the stated total.
Australian Consumer Law protections apply when purchasing NAS hardware and drives from Australian retailers. Under Australian Consumer Law, the retailer cannot refuse to assist by directing you to the manufacturer; consumers may also have specified rights against a manufacturer or importer. Synology, QNAP, and Asustor do not have service centres in Australia. Before buying, ask your retailer about their warranty process, especially for replacements. See our retailer guide for more detail on which Australian stores offer the best after-sales support.
Quick Capacity Reference Table
Use this table to quickly identify the right configuration for your needs. All usable capacity figures assume RAID 5 for 4-bay configurations and RAID 1 for 2-bay configurations.
NAS Capacity Quick Reference
| 2-bay (2x4TB) | 2-bay (2x8TB) | 4-bay (4x4TB) | 4-bay (4x8TB) | 4-bay (4x16TB) | |
|---|---|---|---|---|---|
| Raw Capacity | 8 TB | 16 TB | 16 TB | 32 TB | 64 TB |
| Usable (RAID 1 or RAID 5) | 4 TB | 8 TB | 12 TB | 24 TB | 48 TB |
| Suits (Home) | Individual user | Couple or light family use | Small family | Family with media | Power user or home lab |
| Suits (Business) | Too small | Remote worker backup | Micro business (1-3 staff) | Small office (5-10 staff) | Medium office (10-20 staff) |
| Approx. Drive Cost (AUD) | ~$400 | ~$650 | ~$800 | ~$1,300 | ~$2,400 |
| 3-Year Growth Headroom | Limited | Moderate | Good | Strong | Excellent |
Our NAS Sizing Wizard applies the capacity planning logic from this guide interactively. Enter your use case, user count, and growth estimate and it outputs a recommended bay count and drive size.
See also: our complete Synology NAS Australia guide.
See also: our complete QNAP NAS Australia guide.
How much NAS storage does a typical Australian home need?
Most Australian households need between 4 and 24 TB of usable NAS storage. A couple with moderate photo and document storage can get by with a 2-bay NAS and 4-8 TB usable. A family with multiple devices, a photo library, home videos, computer backups, and possibly Plex should aim for a 4-bay NAS with 16-24 TB usable. Always calculate based on current data plus 3-5 years of growth.
Is a 2-bay NAS enough or should I get a 4-bay?
A 2-bay NAS is enough for individual users with modest storage needs. Personal photos, documents, and one or two computer backups. However, a 4-bay NAS is almost always the better long-term investment. It supports RAID 5 (which a 2-bay cannot), offers more expansion room, and the price difference between a 2-bay and 4-bay model is often only $100-200 AUD. If you are unsure, the 4-bay is the safer choice. You can start with fewer drives and add more later.
How much storage do I lose to RAID?
It depends on the RAID level. RAID 1 (mirroring) uses 50% of your raw capacity for redundancy. So 2 x 8 TB gives 8 TB usable. RAID 5 uses the equivalent of one drive for parity. So 4 x 8 TB (32 TB raw) gives approximately 24 TB usable. RAID 6 uses two drives for parity. So 4 x 8 TB gives approximately 16 TB usable. Additionally, drives report slightly less usable space than labelled due to differences between decimal and binary measurement, so expect another 7-10% reduction from the numbers above.
Can I add more storage to my NAS later without losing data?
Yes, in most cases. If the NAS has empty bays, supported RAID types and software configurations may allow drives to be added without deleting existing data; verify the exact vendor expansion procedure first. If all bays are full, you can replace drives one at a time with larger ones, rebuild the array after each swap, and then expand the volume once all drives are replaced. Synology's SHR makes this particularly straightforward. Both processes preserve your existing data, though rebuilds take time. Potentially 24-48 hours per drive for large capacities. You can also add an expansion unit (Synology DX or QNAP TR series) for additional bays.
Do I need NAS-specific hard drives or can I use regular desktop drives?
You should use NAS-rated drives such as the Seagate IronWolf or WD Red series. These drives are designed for 24/7 operation in a multi-drive enclosure, with firmware optimised for RAID environments and better vibration tolerance. Desktop drives may lack NAS-specific RAID firmware, workload ratings and vibration features; use drives validated for the NAS model and intended workload. NAS drives also carry longer warranties. 3 years standard and 5 years for Pro models. The price difference is modest and well worth it for a device holding your important data. See our NAS hard drive guide for current Australian pricing and recommendations.
How much storage do I need for Plex?
It depends entirely on your media library size and quality preferences. A typical 1080p movie file is 4-15 GB. A 4K movie is 20-80 GB. A TV series season at 1080p is 10-40 GB. A moderate Plex library of 200 movies and 30 TV series at 1080p might consume 2-6 TB. A large 4K library could easily exceed 20 TB. For most Plex users, a 4-bay NAS with 4 x 8 TB drives in RAID 5 (24 TB usable) provides a solid starting point with room to grow.
How long does it take to back up my NAS to the cloud on Australian NBN?
At theoretical line rate, 1 TB takes about 4.6 days at 20 Mbps or 2.3 days at 40 Mbps; 10 TB takes about 46 or 23 days respectively, before protocol overhead, congestion and interruptions. After the initial seed, incremental backups are much faster since only changed files are uploaded. Some cloud backup providers offer drive shipping services to speed up the initial upload. Factor your NBN upload speed into your backup planning. If you have 20+ TB on your NAS, a full cloud backup may not be practical without a higher-tier NBN plan.
Ready to choose the right NAS for your storage needs? Our best NAS guide for Australia compares every major brand and model with current Australian pricing and independent recommendations.