NetCDF files with 1.2GB or more gives error message in a ssh remote session

[bramiup]

Describe the bug

A NetCDF file larger than rougly 1.2 GB cannot be viewed using the H5web on remote (via ssh) Folder.

Instead, I get this error message in VScode:

HDF5-DIAG: Error detected in HDF5 (1.14.2) thread 0: #000: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5F.c line 836 in H5Fopen(): unable to synchronously open file major: File accessibility minor: Unable to open file #001: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5F.c line 796 in H5F__open_api_common(): unable to open file major: File accessibility minor: Unable to open file #002: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5VLcallback.c line 3863 in H5VL_file_open(): open failed major: Virtual Object Layer minor: Can't open object #003: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5VLcallback.c line 3675 in H5VL__file_open(): open failed major: Virtual Object Layer minor: Can't open object #004: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5VLnative_file.c line 128 in H5VL__native_file_open(): unable to open file major: File accessibility minor: Unable to open file #005: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5Fint.c line 2003 in H5F_open(): unable to read superblock major: File accessibility minor: Read failed #006: /__w/libhdf5-wasm/libhdf5-wasm/build/1.14.2/_deps/hdf5-src/src/H5Fsuper.c line 392 in H5F__super_read(): file signature not found major: File accessibility minor: Not an HDF5 file

Such file can be opened within a local session. The documentation says, the limit in a remote session is 2GB. Opening a file >2GB indeed shows a file handle to open the file manually, which works.

To Reproduce

1. Download the test file from here: test.nc (1.2GB)
2. Install the H5web extension in vscode in a remote session
3. Open the file in vscode in a remote session
4. Instead of showing the content, the error message above is displayed.

Expected behaviour

The file should be opened without an error message, or show a file open dialog as it does for files >2GB.

Context

Local OS: Kubuntu Remote CentOS Linux release 8.2.2004

• OS:
  • Local OS: Kubuntu 24.04.03 LTS
  • Remote OS: CentOS Linux release 8.2.2004 (HPC system)
• H5web version:

H5web Version 0.2.0, Last Updated 2025-10-08, 10:12:25

• vscode version:

Version: 1.104.2
Commit: e3a5acfb517a443235981655413d566533107e92
Date: 2025-09-24T11:21:37.073Z
Electron: 37.3.1
ElectronBuildId: 12404162
Chromium: 138.0.7204.235
Node.js: 22.18.0
V8: 13.8.258.31-electron.0
OS: Linux x64 6.8.0-84-generic

[jbphyswx]

I find this can happen with files far smaller than 1GB. It seems to be more common when the extension has files open (and/or maybe even cached) in other tabs.