Hi Håkon,
It is with our experience in HPC that we are looking with big interest at the implementation of the VTK HDF which could become an open-source alternative to our existing proprietary solution ; we even accompany it.
The criteria of performance, storage volume but above all scalability are important for us both in massively parallel writing and in reading (by the writing code or another than by the analysis tool) in different forms of execution.
In fact, our evaluation covers both the VTK HDF implementation and HDF itself.
The devil is always in the detail, which is why it is interesting to exchange in order to adapt and evaluate in a different context.
Concerning the VTK HDF reader, and depending on the uses we make of it, we notice in certain cases significant losses in performance (indicated above); nothing blocking for the moment even if it raises a worrying signal when we increase the number of cells and partitions.
I completely agree with you on the low priority of setting up an “intelligent” VTK HDF writer, nevertheless the reflection/proposal addressed here by Kitware allows us to find solutions to the difficult points that we had identified.
Thus, and I have only just assimilated it, ExternalLink allows you to share common information written in another file such as the list of times or the values of global fields. 