Proxmox Backup Server S3 backend – “Conditional object PUTs are not supported” (OVH Object Storage)

[kamranonline]

Hello,


I’m trying to configure a Proxmox Backup Server datastore on OVH Object Storage using the S3 backend.


The S3 client is set up in PBS and the bucket is accessible, but when I start a backup, I get the following errors during chunk upload:

<?xml version='1.0' encoding='UTF-8'?>
<Error>
  <Code>NotImplemented</Code>
  <Message>Conditional object PUTs are not supported.</Message>
  <RequestId>...</RequestId>
</Error>

TASK ERROR: access time safety check failed: failed to upload chunk to s3 backend:
chunk upload failed: unexpected status code 501 Not Implemented

What I have tried:

• Confirmed the bucket exists and the PBS S3 client can list it.
• Tested connectivity – PBS can list objects.
• Endpoint is OVH’s “Object Storage – S3 API” endpoint for the region.
• --path-style-access 1 is enabled.

Environment:

• PBS version: pveversion --version output here.
• OVH Object Storage (S3 API, likely Swift-backed).

Question:
Does PBS require the S3 backend to support conditional PUTs (If-None-Match: *)? It seems OVH’s S3 API doesn’t implement this, leading to the 501 error.
Is there any way to work around this in PBS, or do I need an S3 service that supports conditional PUTs (e.g. AWS S3, Wasabi, Backblaze B2, etc.)?


If anyone has successfully used PBS with OVH Object Storage, could you share the exact endpoint and settings you used?


Thanks in advance!

 

[Chris]

Does PBS require the S3 backend to support conditional PUTs (If-None-Match: *)? It seems OVH’s S3 API doesn’t implement this, leading to the 501 error.
Is there any way to work around this in PBS, or do I need an S3 service that supports conditional PUTs (e.g. AWS S3, Wasabi, Backblaze B2, etc.)?

HI,
you can use the provider quirks Skip If-None-Match header in the advanced options of the s3 endpoint create/edit window to disable the conditional uploads.