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NASA NTRS2019

OPeNDAP and HDF5 in the Cloud: Techniques and Best Practices for Serving HDF5 Data

In our talk we will discuss considerations and best practices for organizing data and metadata in HDF5 files when serving ESDIS products in S3 with OPeNDAP. The first part of the talk will be devoted to the best practices for organizing data and user-defined metadata including CF conventions in HDF5. We will also address interoperability with netCDF-4 and its role in accessing data in HDF5. In the second part of the talk we will go over OPeNDAP considerations for S3 access to HDF5 data.

HDF5↗

NASA NTRS2018

Overcoming Pitfalls When Using HDF5 Compression

Compression of large datasets in S-NPP, JPSS and other HDF5 data files may substantially reduce their size, in turn reducing disk space requirements and file download time. However, mismatches between the layout of the files' datasets, the HDF5 instance's cache settings, choice of compression algorithm, and the access pattern of applications using the data can sometimes result in poor performance or exhausting machine resources when running the application. Whether designed in advance or modified in response to encountered problems, applications can be tuned to optimize efficiency of data access, avoid unnecessary repeated decompression, and reduce the amount of memory used. Examples will be given of problems that may be encountered, how to use available tools to diagnose or work around them, changing cache settings to conserve memory, and designing access strategies to avoid both performance and memory issues when creating or modifying applications.

performance↗