Transfer files from Backblaze B2 to iCloud Drive
Server to server, without downloading anything to your computer.
How it works
Connect both accounts once. ShiftMyData then talks to Backblaze B2 and iCloud Drive directly and streams the files between them in memory — nothing is written to our disks, and nothing travels down to your machine and back up again. The job runs on a worker, so closing the tab does not stop it.
Will every file be verified?
iCloud Drive exposes no checksum through its API, so files are compared on size and modification time. That is a limit of iCloud Drive rather than of the transfer, and it applies whichever tool you use.
Before you start
- The largest single file iCloud Drive accepts is 50 GB. A bigger one is reported as failed and the rest of the transfer carries on.
- Backblaze B2 treats Report.pdf and report.pdf as two files; iCloud Drive treats them as one. Where both exist in one folder, only one arrives, so rename one first.
- Backblaze bills downloads beyond three times your average stored data in a month, so moving everything out at once can be billed by Backblaze.
- A transfer copies each file's current content, name and modification time; sharing and version history stay behind on Backblaze B2. Business migration carries them where both sides support them.
Sources: www.backblaze.com · www.backblaze.com
Worth knowing about Backblaze B2
B2 charges nothing for uploads, and downloads are free up to three times what you store in a month, which makes it a cheap destination. Moving a whole archive back out in one month can pass that allowance, so check before you start.
Worth knowing about iCloud Drive
Apple publishes no official API for iCloud Drive. The connection uses an unofficial one, signed in with your Apple ID password and a code Apple shows on your device, and Apple can change it without notice -- so treat iCloud as best-effort rather than as something to schedule a nightly job against.
Steps
- On the Clouds screen, add Backblaze B2: paste an application key ID and key from the Backblaze console, ideally one limited to the bucket involved.
- Add iCloud Drive the same way: enter your Apple ID and password, then the code Apple shows on one of your devices.
- Pick the source bucket or prefix in the left pane and the destination folder in the right.
- Choose a mode — copy, mirror, move, or two-way — and start the transfer.
- Leave it. Progress is on the Jobs screen, and a webhook can tell you when it ends.
Questions
Do I have to download my files from Backblaze B2 first?
No. The transfer is streamed from Backblaze B2 to iCloud Drive on our servers, so nothing is written to your machine and your home upload speed is not the limit.
What happens if I close my laptop?
The job keeps running. It is queued on a worker rather than in your browser, and the progress is there when you come back.
How do I know every file arrived?
iCloud Drive exposes no checksum through its API, so files are compared on size and modification time. That is a limit of iCloud Drive rather than of the transfer, and it applies whichever tool you use.
Is there a size limit?
None imposed by us. What you move is drawn from your prepaid allowance (30 GB free, then 500 GB for ₹100 or 2,500 GB for ₹500, each valid a year). iCloud Drive takes single files up to 50 GB, and its own storage quota applies.