Why Fast Origin Transfer is significantly higher than Vercel Blob usage

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1

Problem

Since a couple of days the Fast Origin Transfer started to increase; over the last couple of days it has been about 1TB.

Current Behavior

When I dig deeper into the numbers, it seems to be all caused by Outgoing traffic and by Blob Stores (both 99.9%). The strange thing is when I go to the blob store it mentions, it will say that the data transfer is only 11 GB.

I have no idea how this blob store can cause 1TB of outgoing traffic.

Metrics for the blob store:

  • Data stored: 22GB
  • Simple operations: 2.2k
  • Advanced operations: 111
  • Reported traffic: 11 GB

What I’ve Tried

  • Observability: When I open the blob with Observability, it only lists the 11 GB as well.
  • Logging: I put some extra logging on any code that touches the blob store, but nothing shows up; it’s all regular traffic.
  • Project Isolation: I can’t link it back to a single project, however since the blob is only used by 1 project I assume it’s that project.

Under Observability → Query, looked for Total Fast Origin Transfer under middleware and functions invocations, both are less than 1 gb over the last 14 days for all projects.

Can anyone please give me some pointers on how to find out what’s causing this massive 1TB of outgoing transfers? The data seems to contradict, since the blob store only reports 11GB of traffic.

1 Like
5

A couple of questions:

  • Can you check your team’s Usage tab and filter by project to see if the Fast Origin Transfer is actually coming from a different source?
  • Are you using any Functions or API routes that might be fetching from the Blob store repeatedly?
  • Do you have any automated processes or bots that might be hitting uncached Blob URLs?
  • Check if you’re using Vercel Image Optimization with Blob images (this uses Fast Data Transfer, not Blob Data Transfer)

Thanks!

6
  1. The project filter works really weird. For example, when I select a project, then deselect and select another, nothing will show. Only when I select 3 project or more the fast origin transfer data shows up. Then it doesn’t matter which combination of projects I use it will always show. There’s also a projectId without a name. When I enter that in the url vercel.com/myteam/id I get a 404
  2. Yes, there’s a cron job that uses data from the blob. On a typical day I would say it fetches from the Blob 10 times
  3. Not that I’m aware. The application is only available for logged in users. And the API routes upload the file to a different API, they don’t share the URLs
  4. Under fast data transfer, there’s only about 5GB total transfer for all of my project for the last 7 days.
7

I might have found something, will keep an eye open to see if the traffic stops now