kerchunk

Cloud-friendly access to archival data

Kerchunk is a library that provides a unified way to represent a variety of chunked, compressed data formats (e.g. NetCDF, HDF5, GRIB), allowing efficient access to the data from traditional file systems or cloud object storage. It also provides a flexible way to create virtual datasets from multiple files. It does this by extracting the byte ranges, compression information and other information about the data and storing this metadata in a new, separate object. This means that you can create a virtual aggregate dataset over potentially many source files, for efficient, parallel and cloud-friendly in-situ access without having to copy or translate the originals. It is a gateway to in-the-cloud massive data processing while the data providers still insist on using legacy formats for archival storage.

Why Kerchunk:

We provide the following things:

• completely serverless architecture
• metadata consolidation, so you can understand a many-file dataset (metadata plus physical storage) in a single read
• read from all of the storage backends supported by fsspec, including object storage (s3, gcs, abfs, alibaba), http, cloud user storage (dropbox, gdrive) and network protocols (ftp, ssh, hdfs, smb...)
• loading of various file types (currently netcdf4/HDF, grib2, tiff, fits, zarr), potentially heterogeneous within a single dataset, without a need to go via the specific driver (e.g., no need for h5py)
• asynchronous concurrent fetch of many data chunks in one go, amortizing the cost of latency
• parallel access with a library like zarr without any locks
• logical datasets viewing many (>~millions) data files, and direct access/subselection to them via coordinate indexing across an arbitrary number of dimensions

For further information, please see the documentation.