Skip to main content

Overview

Persistent Storage, powered by Backblaze, is in Beta. Account owners and admins can join the beta under Settings → Profile, or by ticking Join the beta program at signup. They can leave it the same way, under Settings → Profile. Accounts that haven't joined don't see the Storage page or the storage picker, and the storage API answers 403.

Partner vendors can't use Persistent Storage until general availability.

Persistent Storage keeps your data after an instance is terminated.

  • You create storage and give it a name, such as datasets.
  • You attach it when you deploy an instance, or to an instance you already have.
  • On the instance it appears as a folder: /persistent/<name>.
  • When you terminate the instance, the files stay in the storage.
  • Attach it to your next instance and the files are there.

Use it for datasets, model weights, checkpoints and results you want to keep between instances.

Storage is charged per GB stored per month from your account balance, metered every minute. Downloads, including reads from the mounted storage on your instance, beyond 3x your average stored data per month are $0.05/GB. See Pricing and Billing.

Persistent Storage is object storage behind a filesystem layer. It has higher latency than the instance's local NVMe disk and only partial POSIX behavior. Keep hot data on local disk. See Limitations.

Attaching the same storage to more than one instance at the same time isn't supported and can corrupt your data. Every mount is read-write, and there is no file locking between instances. Attach each storage to one instance at a time: stop the instance that has it and detach it before you attach it to another.

Key facts

Mount path/persistent/<name> on the instance it is attached to
Attach and detachAttach when you deploy, or on an existing instance from My Instances. On an existing instance the change takes effect after you stop and start it. Detach needs the instance stopped.
Storage per instanceUp to 8
Instances per storageOne at a time. Attaching the same storage to several instances at once isn't supported.
Storage price$0.085 per GB per month, charged every minute
SpeedSlower than the instance's local disk. See Limitations.
DownloadsIncludes reads from /persistent on your instances. Free up to 3x your average stored GB each month, then $0.05 per GB
DeleteOnly when no instance has it attached, including stopped instances

See Pricing and Billing for the exact rules.

Where to manage it

  • Website: the Storage page in the sidebar at vm.massedcompute.com/storage, and the Persistent Storage picker on Deploy.
  • REST API: GET, POST and DELETE on /api/v1/storage-volumes, and volumeIds on POST /api/v1/instance/launch. See the API reference.
  • MCP: not available. The MCP server has no storage tools and can't attach storage at launch.

In this section

Mascot