What is the problem you are having with rclone?
When uploading files via multipart upload (using rcat or copy) to the OVHcloud S3 provider, the upload fails whenever --s3-chunk-size is set to any value other than the default 5Mi.
- Changing the
providerfield in the backend definition (AWS,Other, orOVHcloud) does not resolve the issue. - The exact same commands work correctly on other S3-compatible providers (AWS, Backblaze, Hetzner).
- This issue does not occur on older rclone versions: for example, it works correctly with
v1.60.1-DEVon the same machine. - Uploads of small files (that do not trigger multipart upload) also succeed.
Therefore, the problem appears to be specifically related to multipart uploads on OVHcloud when using custom --s3-chunk-size values in rclone v1.71.2.
Run the command 'rclone version' and share the full output of the command.
rclone v1.71.2
- os/version: ubuntu 24.04 (64 bit)
- os/kernel: 6.8.0-87-generic (x86_64)
- os/type: linux
- os/arch: amd64
- go/version: go1.25.3
- go/linking: static
- go/tags: none
Which cloud storage system are you using? (eg Google Drive)
Local storage for source, OVHcloud Object Storage (s3.sbg.io.cloud.ovh.net) for destination.
The command you were trying to run (eg rclone copy /tmp remote:tmp)
cat '/tmp/foo.txt' | rclone rcat -vv --s3-chunk-size 300M ':s3,provider=Other,env_auth=true,region=sbg,endpoint="https://s3.sbg.io.cloud.ovh.net/":bar-bucket/foo.txt'
or
rclone copy -vv --s3-chunk-size 300M '/tmp/foo.txt' ':s3,provider=Other,env_auth=true,region=sbg,endpoint="https://s3.sbg.io.cloud.ovh.net/":bar-bucket/foo.txt'
The rclone config contents with secrets removed.
I do not use a rclone config, I just setup the AWS_ACCESS_KEY_ID and AWS_SECRET_ACCESS_KEY env variables (Allows for command line rclone setup only)
A log from the command with the -vv flag
2025/11/17 14:26:13 DEBUG : rclone: Version "v1.71.2" starting with parameters ["rclone" "rcat" "-vv" "--s3-chunk-size" "300M" ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/foo.txt"]
2025/11/17 14:26:13 DEBUG : Creating backend with remote ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/"
2025/11/17 14:26:13 DEBUG : Using config file from "/home/francois/.config/rclone/rclone.conf"
2025/11/17 14:26:13 DEBUG : :s3: detected overridden config - adding "{qNhzk}" suffix to name
2025/11/17 14:26:13 DEBUG : fs cache: renaming cache item ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/" to be canonical ":s3{qNhzk}:bar-bucket"
2025/11/17 14:26:14 NOTICE: S3 bucket bar-bucket: Streaming uploads using chunk size 300Mi will have maximum file size of 2.861Ti
2025/11/17 14:26:14 DEBUG : foo.txt: open chunk writer: started multipart upload: OWVlYzZhNmUtMmRiNS00MDczLWE1YWUtYTk2MDNkNGUxN2Zh
2025/11/17 14:26:15 DEBUG : foo.txt: multipart upload: starting chunk 0 size 300Mi offset 0/off
2025/11/17 14:26:16 DEBUG : foo.txt: multipart upload: starting chunk 1 size 300Mi offset 300Mi/off
2025/11/17 14:26:16 DEBUG : foo.txt: Cancelling multipart upload
2025/11/17 14:26:16 DEBUG : foo.txt: multipart upload "OWVlYzZhNmUtMmRiNS00MDczLWE1YWUtYTk2MDNkNGUxN2Zh" aborted
2025/11/17 14:26:16 ERROR : foo.txt: Post request rcat error: failed to upload chunk 1 with 314572800 bytes: operation error S3: UploadPart, https response error StatusCode: 400, RequestID: tx902c2682a3cf4ab39f3e2-00691b2277, HostID: tx902c2682a3cf4ab39f3e2-00691b2277, api error IncompleteBody: The request body terminated unexpectedly
2025/11/17 14:26:16 DEBUG : 6 go routines active
2025/11/17 14:26:16 NOTICE: Failed to rcat with 2 errors: last error was: failed to upload chunk 1 with 314572800 bytes: operation error S3: UploadPart, https response error StatusCode: 400, RequestID: tx902c2682a3cf4ab39f3e2-00691b2277, HostID: tx902c2682a3cf4ab39f3e2-00691b2277, api error IncompleteBody: The request body terminated unexpectedly
A log from the same command working nicely under an older RClone version (v1.60.1):
<7>DEBUG : rclone: Version "v1.60.1-DEV" starting with parameters ["rclone" "rcat" "-vv" "--s3-chunk-size" "300M" ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/foo.txt"]
<7>DEBUG : rclone: systemd logging support activated
<7>DEBUG : Creating backend with remote ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/"
<7>DEBUG : Using config file from "/home/francois/.config/rclone/rclone.conf"
<7>DEBUG : :s3: detected overridden config - adding "{qNhzk}" suffix to name
<7>DEBUG : fs cache: renaming cache item ":s3,provider=Other,env_auth=true,region=sbg,endpoint=\"https://s3.sbg.io.cloud.ovh.net/\":bar-bucket/" to be canonical ":s3{qNhzk}:bar-bucket"
<5>NOTICE: S3 bucket bar-bucket: Streaming uploads using chunk size 300Mi will have maximum file size of 2.861Ti
<7>DEBUG : foo.txt: multipart upload starting chunk 1 size 300Mi offset 0/off
<7>DEBUG : foo.txt: multipart upload starting chunk 2 size 300Mi offset 300Mi/off
<7>DEBUG : foo.txt: multipart upload starting chunk 3 size 300Mi offset 600Mi/off
<7>DEBUG : foo.txt: multipart upload starting chunk 4 size 53.674Mi offset 900Mi/off
<7>DEBUG : foo.txt: Dst hash empty - aborting Src hash check
<7>DEBUG : foo.txt: Size of src and dst objects identical
<7>DEBUG : 14 go routines active