How Long Does Cloud Backup Take on NBN? Upload Speed Reality for Australian NAS Users

Cloud backup from a NAS in Australia is limited almost entirely by your NBN upload speed, and the numbers are far worse than most people expect. A household with 4TB of data on an NBN 50 plan (typical upload: 18-20Mbps) will spend 18-22 days just completing the initial backup upload, assuming the NAS runs continuously and the connection is fully dedicated to backup. After the initial upload, ongoing incrementals are manageable, but getting there is a genuine planning problem that most Australians discover too late.

How NBN Upload Speeds Actually Work

NBN plans are sold by download speed, not upload speed. The upload rate you actually get depends on your plan tier and technology type:

• NBN 25: Up to 5Mbps upload (typical: 4-5Mbps, or about 0.6MB/s)
• NBN 50: Up to 20Mbps upload (typical: 18-20Mbps, or about 2.3MB/s)
• NBN 100: Up to 20Mbps upload on most RSPs, though some offer 40Mbps; typical 18-20Mbps
• NBN 250: Up to 25Mbps upload (typical: 23-25Mbps, or about 2.9MB/s)
• NBN 1000: Up to 50Mbps upload (typical: 45-50Mbps, or about 5.8MB/s)

Note that NBN 100 and NBN 50 often have identical upload caps with most RSPs. Upgrading from NBN 50 to NBN 100 may not help your backup speed at all. Check your RSP's upload speed for your specific plan before assuming an upgrade will help.

FTTP (fibre to the premises) connections generally achieve closer to their theoretical maximums. FTTN (fibre to the node) and HFC connections can vary significantly based on distance and network congestion.

Real Backup Times by Data Size and NBN Plan

The formula is straightforward. Time in hours = Data size in GB / (Upload speed in Mbps / 8 / 1024 * 3600). In practice, real-world throughput is 10-20% lower than the theoretical maximum due to encryption overhead, cloud provider ingestion limits, and network variability. The table below uses 80% of theoretical maximum as a realistic working figure.

What Changes After the Initial Upload

The initial backup is the painful part. Once your NAS data is in the cloud, incremental backups are far more manageable. A typical home NAS where a family adds photos, documents, and occasional video generates 5-20GB of new or changed data per week. At NBN 50 upload speeds, that incremental is completed in 30 minutes to 2 hours, usually overnight without any noticeable impact on household internet use.

The problem is getting to that steady state. Most cloud backup applications, including Synology Hyper Backup, Backblaze Personal Backup, and dedicated NAS-to-cloud tools, will run continuously if permitted and can consume your entire upload bandwidth. This causes noticeable slowdowns for other household users during daytime hours.

Practical options for managing the initial upload period:

• Schedule backup for off-peak hours: 11pm-7am when household internet use is low. Most backup applications support scheduling windows. This triples or quadruples your real calendar time but preserves daytime performance.
• Throttle the backup client: Synology Hyper Backup, Backblaze, and most dedicated clients allow bandwidth throttling. Setting an 8Mbps cap during the day and full speed overnight is a common approach.
• Use a seeding service: Some providers (Backblaze included) allow you to ship drives directly and have them ingest your initial backup offline. Backblaze charges for the service but eliminates the initial upload delay entirely.

CGNAT and Upload Speed: A Separate Problem

CGNAT (Carrier-Grade Network Address Translation) is a different issue from upload speed but frequently appears in the same conversation. CGNAT means your connection shares a public IP address with other households, which prevents incoming connections from reaching your NAS without a workaround. CGNAT does not reduce your upload speed for outbound backup. Your backup to Backblaze or Synology C2 will work fine on a CGNAT connection.

Where CGNAT causes problems is remote access to your NAS - reaching your NAS from outside your home network. If you want to access your NAS directly from work or a mobile device, CGNAT blocks the standard port forwarding approach. Solutions include Tailscale, Cloudflare Tunnels, or requesting a static IP from your RSP (often available at low cost). Cloud backup is not affected by CGNAT.

Cloud Provider Upload Limits

Cloud providers can also throttle ingest speed independently of your NBN connection. In practice, the major providers used by NAS owners in Australia do not aggressively throttle initial uploads for consumer accounts:

• Backblaze B2: No documented ingest throttle for standard accounts. Most NAS users report consistent 80-95% of their upload speed available for backup.
• Synology C2: No ingest throttle documented. Performance is generally consistent with connection speed.
• Wasabi: No ingest throttle. Minimum storage charges apply (90-day minimum), which affects cost more than speed.
• Amazon S3 / Glacier: No ingest throttle for standard classes. Glacier ingest is batched, which can slow effective throughput for small files.

For a full cost and performance comparison of the major cloud backup providers relevant to Australian NAS users, see the Backblaze B2 vs Synology C2 vs Wasabi comparison.

Practical Options When the Numbers Don't Work

If the initial backup time is genuinely unworkable given your data size and NBN plan, there are several approaches that Australian NAS users have found effective:

1. Seed from the Cloud Provider's Facility

Backblaze offers a drive seeding service. You ship drives containing your data, they ingest it directly into your B2 account, and ongoing incremental backups run normally over NBN from that point. The service has a fee, but for 8TB+ datasets on slow connections, it can be the only practical option. Not all cloud providers offer this service. Synology C2 does not currently offer seeding for Australian accounts.

2. Select Only Critical Data for Cloud Backup

Not all data on a NAS is equally valuable or difficult to recreate. A practical tiering approach:

• Tier 1 (cloud backup): Irreplaceable originals - photos, personal documents, financial records. Typically 200GB-1TB for most households.
• Tier 2 (local backup only): Media libraries, software installers, ripped content. Large but recreatable from source or acceptable to lose.
• Tier 3 (no backup needed): Downloaded content, temporary files, transcoded media.

Reducing your cloud backup footprint to Tier 1 data only can turn an 8TB cloud backup problem into a 500GB one. This is the approach recommended by the 3-2-1 backup strategy - keep offsite backups focused on irreplaceable data, and let local redundancy handle the rest.

3. Upgrade to NBN 1000 If Available

NBN 1000 (Ultrafast) plans on FTTP connections offer 50Mbps upload, which is meaningfully faster than the 20-25Mbps cap on lower plans. This is the only NBN tier that delivers a material upload speed improvement for most RSPs. If FTTP is available at your address and you have a large backup dataset, the plan upgrade cost may be worth it during the initial backup window, then downgraded afterwards.

Not all addresses have FTTP access. The NBN Co address checker is the authoritative source for what connection type and plan speeds are available at a specific address.

4. Consider Local-Only Offsite for Large Datasets

For very large datasets (10TB+) where cloud backup is genuinely impractical on Australian upload speeds, a local offsite rotation is a valid alternative. This involves keeping a second external drive or small NAS at a trusted location (family member, workplace) and rotating it on a schedule. Not as convenient as cloud, but far more practical for large archives on slow connections. This approach works well as the third copy in a 3-2-1 strategy where the cloud handles a smaller critical subset and the local offsite covers the full dataset.

Australian Section: NBN Plan Reality by State

Connection type availability varies significantly across Australia. FTTP coverage (which enables NBN 1000 and its 50Mbps upload) is concentrated in newer housing estates and areas that received the original NBN rollout design. Older areas in capital cities often have FTTN or HFC connections, which cap out at 20-25Mbps upload regardless of plan tier.

Regional and rural Australia predominantly uses Fixed Wireless or Satellite (Sky Muster or Starlink). Fixed Wireless upload speeds are typically 5-10Mbps. Sky Muster satellite upload is heavily latency-affected and not suitable for large backup jobs. Starlink is increasingly common in regional AU and provides 5-20Mbps upload with lower latency than Sky Muster, though upload consistency varies.

For Starlink users specifically: cloud backup works, but the upload speed is similar to or slightly worse than NBN 50 in practice, and latency-sensitive backup protocols may need to be adjusted. See the NAS for Starlink Australia guide for specific configuration advice.

How long does the initial cloud backup take on NBN 50?

At NBN 50's typical 18-20Mbps upload (about 2.3MB/s effective), expect roughly 5 days per terabyte of data at full speed. A 2TB backup takes around 10-12 days; a 4TB backup takes 20-25 days. These estimates assume 80% of theoretical throughput and continuous backup without throttling. Scheduling backup only during off-peak hours (overnight) can extend real calendar time to 2-3x longer but preserves daytime internet performance.

Does upgrading from NBN 50 to NBN 100 speed up cloud backup?

Usually not. Most Australian RSPs cap NBN 100 upload at 20Mbps, the same as NBN 50. The upload speed tier does not change between NBN 50 and NBN 100 with most providers. Check your RSP's plan details for the specific upload speed offered on each tier. If both show 20Mbps upload, upgrading will not help backup times.

Will CGNAT stop my NAS from backing up to the cloud?

No. CGNAT only affects incoming connections to your home network. Cloud backup is outbound - your NAS connects to the cloud provider's servers, not the other way around. CGNAT does not affect upload speed or backup reliability. Where CGNAT causes problems is remote access to your NAS from outside your home network, which requires a workaround like Tailscale or a Cloudflare Tunnel.

Which cloud backup providers work best with Australian NAS systems?

Backblaze B2, Synology C2, and Wasabi are the three most commonly used by Australian NAS owners. Backblaze B2 has the most third-party application support (compatible with Synology Hyper Backup, QNAP HBS3, and most backup tools). Synology C2 is tightly integrated with DSM but limited to Synology NAS hardware. Wasabi charges no egress fees but has a 90-day minimum storage policy. All three have infrastructure outside Australia with no AU-specific throttling on ingest. For a detailed comparison of costs and features, see the Backblaze vs Synology C2 vs Wasabi comparison.

Is cloud backup even worth it for large NAS setups in Australia?

For large datasets (10TB+) on standard NBN upload speeds, full cloud backup is often impractical as a primary offsite strategy. A realistic approach is tiered backup: use cloud for irreplaceable critical data (documents, photos, records - typically under 1TB for most households) and use a local offsite rotation for the full dataset. This keeps the cloud backup window manageable while maintaining offsite protection for your most valuable data. Cloud-only backup of everything is practical for datasets under 2TB on NBN 100 or better connections.

Can I speed up my initial backup by connecting my NAS directly to my router?

Yes, a wired Ethernet connection between your NAS and router is always faster and more stable than Wi-Fi for backup. However, the bottleneck in cloud backup is not your local network - it is your NBN upload speed. Even at 1GbE local speeds, the NAS is still limited to your 20-25Mbps WAN upload. A wired connection removes one variable (Wi-Fi interference and throughput variability) but does not change the fundamental upload ceiling imposed by your NBN plan.