Hello Wei,

I am afraid I have never seen this particular error. Some items in an HDF5 are size limited, eg an "attribute" must no be larger than 64k or so. This may be similar.

Of the CarpetIOHDF5 options I would not try and change any of the chunking or similar options away from the the defaults since they may not be well tested.

Could you perhaps attach the full parameter file (*.par file) and the full stdout and stderr log file to the email? Also the backtrace.txt file might be useful to see exactly what triggers the error.

Similar error messages can be found on the web eg

https://github.com/HDFGroup/hdf5/issues/3762

though the solution suggested there seems to be to modify and recompile HDF5 itself.

The suggestion

H5Pset_libver_bounds(fapl, H5F_LIBVER_V110, H5F_LIBVER_V110);

is doable at runtime though, but needs to be done when writing to the file it would seem (in CarpetIOHDF5 and I think there are already some fapl set up when creating a file so this would be straightforward to add).

Note that this may all not matter if one uses the default setup that writes one file per MPI rank. I would also (strongly) suggest to not append to HDF5 files (if you restart from a checkpoint) since, due to HDF5 files being fragile while open, this can easily corrupt the whole file and make it unreadable if the code crashes while writing.

I am somewhat surprised that the issue happens in a H5Cload and not a write function.

Yours, Roland

On Tue, 1 Oct 2024 19:35:20 -0400, Wei Sun wrote:

Hi Roland,

Thank you for your clarification. I think I missed the true error, so the actual error is here:

*WARNING level 1 from host* x1005c1s1b0n1h0.chn.perlmutter.nersc.gov, process 0 in thorn CarpetIOHDF5, file /Cactus/configs/sim/build/CarpetIOHDF5/Output.cc:442: -> Values for DISTRIB=CONSTANT grid variable 'TERMINATIONTRIGGER::watchminutes' (timelevel 0) differ between processors 0 and 383; only the array from processor 0 will be stored. *cactus_sim: H5C.c:6732: H5C_load_entry: Assertion entry->size < ((size_t)(32 * 1024 * 1024)) failed.* Rank 0 with PID 1727399 received signal 6. Writing backtrace to /Multipole/backtrace.0.txt srun: error: nid004365: task 0: Aborted.

Then I modified my parameter file by setting IO::out_mode = "proc" to make the checkpoint.h5 file chunked, which fixed the aborted issue. However, this also changed my 3D output HDF5 file to chunked format as well.

Even after adding out_unchunked='yes' in the out_vars parameter, for example: CarpetIOHDF5::out3D_vars = "HydroBase::rho{out_unchunked='yes'}", it doesn't work.

Is it possible that I didn’t write it in the correct way?

Thank you,

Wei