docs: second part of the archive page, using archives with your own S3

[devin-ai-integration]

Summary

The archive page only covered the managed flow (sandbox.archive() / unarchive()). This adds a second part documenting the sandbox-api surface behind it, so users can write the same archive to a bucket they own and restore it later: backups, cross-workspace or cross-region copies, keeping several archives of one sandbox.

New sections under ## Archive to your own storage:

• Archive contents: uncompressed tar, .blaxel-archive/manifest.json (with a sample manifest) and .blaxel-archive/processes.json, deletions carried in the manifest rather than as tar members, and what is never archived (memory, /tmp, runtime dirs, host-injected identity, volumes and drives).
• POST /archive/export on sandbox.metadata.url, with the option table (url, async, dryRun, saveProcesses, excludes, headers, multipart) and the mk3.0 imageDevice: /dev/ukp_rom0 note.
• Dry run to get the exact size before presigning, since the archive is streamed with a length announced up front.
• Multipart for archives above 5 GB, including the 5 MB minimum part size and why abortUrl matters.
• Cold storage backups through signed headers (x-amz-storage-class), and saveProcesses: false for a filesystem-only archive.
• Following an export on GET /archive/status, and the fact that the freeze is not lifted after a successful export (POST /archive/resume).
• Restoring by setting BL_ARCHIVE_IMPORT_URL at sandbox creation: restore phases, processes relaunched with new IDs, import applied once, and the quarantine behavior after a partial restore.
• A short list of caveats: presigned URLs are credentials, the one hour transfer bound, same-image requirement, format version and gzip support, one export at a time.

Content checked against sandbox-api/src/handler/archive/* (export, import, tar, multipart, transport, quiesce, restore) and the controlplane archive manager.

Link to Devin session: https://app.devin.ai/sessions/f05412800720448383d385d1ff7121fe
Requested by: @drappier-charles

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR that start with 'DevinAI' or '@devin'.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring

[mintlify]

Preview deployment for your docs. Learn more about Mintlify Previews.

Project	Status	Preview	Updated (UTC)
blaxel	🟢 Ready	View Preview	Aug 27, 2026, 12:37 AM

[devin-ai-integration]

Devin Review found 1 potential issue.

[devin-ai-integration]

🔍 Manifest excludes sample omits hostname/hosts

The sample excludes (Sandboxes/Archive.mdx:160) lists only etc/resolv.conf, while the prose (Sandboxes/Archive.mdx:176) says host-injected identity also covers /etc/hostname and /etc/hosts. Confirm the sample matches the real default exclude set so readers are not misled.

---

Was this helpful? React with 👍 or 👎 to provide feedback.