You start uploading a 20 GB folder before bed, and in the morning you find the progress bar frozen at 90 percent, or an error that means starting over. It's one of the most maddening experiences in cloud storage, and it usually isn't your fault. It's a consequence of how uploads traditionally work.
Why big uploads fail
A traditional upload sends the whole file in one long request. The longer that request runs, the more things can interrupt it:
- A brief Wi-Fi drop or a router restart breaks the connection, and the request cannot continue.
- The computer or phone goes to sleep, or the browser tab is suspended to save memory.
- Servers and proxies often limit how long a single request may last, or how large it can be. Many default to tens of megabytes.
- Mobile networks switch towers or move between Wi-Fi and data, which can drop the connection.
- VPNs and corporate firewalls sometimes cut long-running transfers.
With a simple upload, any of these means starting from zero. The bigger the file, the longer the exposure, which is why the failures cluster on large files.
How resumable uploads work
A resumable upload breaks the file into chunks and keeps track of how much the server has received. If the connection drops, the client asks the server how many bytes it has and continues from there instead of starting over. An open protocol called tus (tus.io) standardizes this approach, and it's widely used for large file transfers.
- The client tells the server it wants to upload a file of a given size and gets back an upload address.
- It sends the file in chunks, and the server records how many bytes it has stored.
- If the connection breaks, the client asks the server for the current offset.
- The client resumes from that point and finishes the transfer.
The result is that a failed connection costs you seconds, not hours. It also means you can close the laptop, come back, and pick up where you left off, as long as the upload session is still valid.
How long will it take?
Upload speed, not download speed, sets the pace, and many home connections are much slower in that direction. These times assume the connection is fully used and don't include overhead, so allow ten percent or more.
| File size | At 10 Mbps | At 20 Mbps | At 50 Mbps |
|---|---|---|---|
| 1 GB | About 13 minutes | About 7 minutes | About 3 minutes |
| 10 GB | About 2 hours 15 minutes | About 1 hour 10 minutes | About 27 minutes |
| 50 GB | About 11 hours | About 5 hours 30 minutes | About 2 hours 15 minutes |
| 100 GB | About 22 hours | About 11 hours | About 4 hours 30 minutes |
Practical tips
- Use a wired connection, or sit close to the router on a 5 GHz Wi-Fi band.
- Turn off sleep while an upload is running, and keep laptops plugged in.
- Keep the browser tab or app open and in the foreground if the service requires it.
- Avoid running a VPN during large uploads unless you need it.
- Start big uploads in the evening so they run overnight when nobody else is using the connection.
- Upload in batches: the irreplaceable files first, the bulk archive afterwards.
Many small files versus one big file
Thousands of tiny files can upload more slowly than a single file of the same total size, because each file has its own overhead. If you have a folder of ten thousand small files that you'll never need to open individually, zipping it into one archive can speed things up. If you want to browse and preview them online, upload them unzipped and be patient.
What to look for in a service
- Resumable uploads that survive dropped connections.
- Clear progress and the ability to pause and continue.
- No arbitrary limit on single file size that stops large videos.
- An upload that doesn't restart if you refresh the page.
NGDS uploads use the open tus protocol, so an interrupted upload continues from where it stopped instead of starting again, which is exactly what you want when you're sending a large video or a full photo shoot.