Downloading issues

Using SimScale
1

Hi everyone,

I’m running a steady-state incompressible case (SIMPLE, k-omega SST, ~15.3 M cells, four meanVelocityForce momentum sources) and I’ve hit a wall with downloading results, so I’d appreciate any advice.

The problem

The SOLUTION_FIELDS component for one run is reported as 34 GB (a later, shorter run is ~17 GB). Downloading it is unreliable because the transfer cannot be resumed — if the connection drops once, it restarts from byte 0. In practice I could not complete the 34 GB package.

What the server returns

http

GET /api/v2/load/projects/<projectId>/results/<resultUuid>/components/<componentUuid>/solutions?token=<redacted>&uid=<redacted>
Range: bytes=0-1023

http

HTTP/1.1 200                      <-- expected 206 Partial Content
Content-Type: application/octet-stream
Content-Disposition: attachment; filename="result.zip"
Transfer-Encoding: chunked        <-- no Content-Length
Via: 1.1 ...cloudfront.net (CloudFront)
X-Amz-Cf-Pop: FRA56-P10
Alt-Svc: h3=":443"; ma=86400

Observations:

  • I sent Range: bytes=0-1023 and got 200, not 206.
  • There is no Content-Range header and no Accept-Ranges header.
  • The response is chunked with no Content-Length.

My guess is that because the origin streams the archive, CloudFront cannot serve range requests for it — but I’d be glad to be corrected.

What I have already tried

Method Result
curl (plain) drops mid-transfer; no way to continue
curl --retry-all-errors worse — it truncates the partial file and restarts from 0
curl -C - (resume) cannot work, since the server ignores Range
Windows BITS (Start-BitsTransfer) fails immediately with a TLS error: “A security channel could not be supported”
Edge browser download also restarts from the beginning on a drop

I’m located in Shanghai, and my requests appear to be served by the Frankfurt PoP (X-Amz-Cf-Pop: FRA56-P10), which may be part of why the connection is fragile.

My questions

  1. Is resumable download of SOLUTION_FIELDS supported at all? If there is a supported way to get Range/206 behaviour, or to download the package in multiple parts, I’d love to know how.

  2. Can individual files inside the result package be retrieved without downloading the whole archive? This is what would really solve my problem. I only need a handful of small files, for example:

    file inside the package approximate size
    <time>/uniform/momentum_source_0_0Properties.gz … _3_0Properties.gz a few hundred bytes each
    system/controlDict ~1 KB
    <time>/uniform/cumulativeContErr.gz ~400 bytes
    <time>/phi.gz ~236 MB

    Needing 17–34 GB to obtain a few kilobytes is the actual blocker for my analysis.

  3. If neither is possible, is there a recommended way to transfer very large result packages reliably (a CLI tool, a direct storage URL, an endpoint/region choice, or simply “download from a different network”)? A definitive “this is not supported” answer is also useful — then I can at least plan disk space and transfer windows.

Notes

  • The small companion components are fine — RESIDUALS_PLOT, INLETS_PLOT, OUTLETS_PLOT, DOMAIN_PLOT, WALLS_PLOT all download without trouble (they’re a few hundred KB). It’s only the large SOLUTION_FIELDS archive that is problematic. This is actually why I’m asking question 2 — those small components are served per-component, so I hoped the same might be possible for individual files.
  • I’m happy to share the project / run / component UUIDs privately if a staff member wants to reproduce this.

Thanks in advance for any pointers — even a “not supported, here’s what people usually do” would help me plan.