hdf5filters

A collection of HDF5 compression filters, wrapped in a cmake build system.

The implementation of the compression algorithms and filter code are imported from various open-source projects, without modifications.

The purpose of this module is to pull together a selection of high performance compression algorithms with implementations of HDF5 dynamically loadable filters and provide a sensible (cmake based) build system.

LZ4

Extremely Fast Compression algorithm: http://www.lz4.org

Code: https://github.com/lz4/lz4

Log:

Date	version	SHA
29 April 2017	v1.7.5	7bb64ff2b69a9f8367de9ab483cdadf42b4c1b65

h5lzfilter

Dynamically loadable HDF5 filter using LZ4 compression.

Code: https://github.com/nexusformat/HDF5-External-Filter-Plugins/tree/master/LZ4/src

Log:

Date	version	SHA
29 April 2017	N/A	863db280bcb3a120849bcedd75426af6f55dce12

bitshuffle

Filter for improving compression of typed binary data. Includes implementation of a HDF5 dynamically loadable filter.

Code: https://github.com/kiyo-masui/bitshuffle

Log:

Date	version	SHA
29 April 2017	0.3.3.dev1	762e5d7ef27ccc3d975546cc281609fb6464b563

Blosc

Filter utilizing the Blosc meta compressor. Blosc is an external dependency and this module only includes the HDF5 dynamically loadable filter code. Blosc combines a number of popular compression algorithms like LZ4, Snappy, zlib, etc and enable multi-threaded and highly optimized use of these.

Code: https://github.com/blosc/hdf5-blosc

Log:

Date	version	SHA
12 July 2018	N/A	efa7653f0735cd03e7e9efb94f3ebcbcbec42889

Build and install

Requirements: HDF5 C library and headers version >= 1.8.11

Recommendation: build on/for a processor with Intel AVX2 support for best performance. The following flags can be used to control what optimisations are enabled:

• CMAKE_BUILD_TYPE=Release will enable compiler optimizations: -O3
• CMAKE_BUILD_TYPE=RelWithDebInfo will enable compiler optimizations: -O2
• USE_SSE2=ON will enable SSE2 extensions: -msse2 (default: ON)
• USE_AVX2=ON will enable AVX2 extensions: -mavx2 (default: OFF - use gcc >= 4.8)

cd hdf5filters
mkdir -p cmake-build
cd cmake-build
cmake -DHDF5_ROOT=/path/to/hdf5/installation/ \
      -DBLOSC_ROOT_DIR=/path/to/blosc/installation \
      -DCMAKE_INSTALL_PREFIX=/path/to/install/destination \
      -DCMAKE_BUILD_TYPE=Release \ 
      -DUSE_AVX2=ON \
      ..
make
make install

The compression libs are installed into the CMAKE_INSTALL_PREFIX/lib dir and the HDF5 filters are installed into the CMAKE_INSTALL_PREFIX/h5plugin dir.

Usage

Set the environment variable HDF5_PLUGIN_PATH to point to the CMAKE_INSTALL_PREFIX/h5plugin dir. Use semicolon to list multiple dirs. Then use HDF5 (>= 1.8.11) applications as per usual and the filters will automatically be loaded when required.

export HDF5_PLUGIN_PATH=/path/to/hdf5filters/installation/h5plugin

Using the HDF5 tools with filters

The HDF5 (>=1.8.12) tool h5repack can be used to decompress a compressed dataset.

First check out the '/data' dataset in compressed.h5 and notice the FILTER_ID = 320004 is the HDF5 lz4 filter:

h5dump -Hp compressed.h5 
HDF5 "compressed.h5" {
GROUP "/" {
   DATASET "data" {
      DATATYPE  H5T_STD_I64LE
      DATASPACE  SIMPLE { ( 1000 ) / ( 1000 ) }
      STORAGE_LAYOUT {
         CHUNKED ( 1000 )
         SIZE 4018
      }
      FILTERS {
         UNKNOWN_FILTER {
            FILTER_ID 32004
            
            COMMENT HDF5 lz4 filter; see http://www.hdfgroup.org/services/contributions.html
         }
      }
      FILLVALUE {
         FILL_TIME H5D_FILL_TIME_ALLOC
         VALUE  0
      }
      ALLOCATION_TIME {
         H5D_ALLOC_TIME_INCR
      }
   }
}
}

To decompress the '/data' dataset in the file compressed.h5 to bloated.h5:

h5repack -f data:NONE compressed.h5 bloated.h5

Now check the result:

HDF5 "bloated.h5" {
GROUP "/" {
   DATASET "data" {
      DATATYPE  H5T_STD_I64LE
      DATASPACE  SIMPLE { ( 1000 ) / ( 1000 ) }
      STORAGE_LAYOUT {
         CHUNKED ( 1000 )
         SIZE 8000
      }
      FILTERS {
         NONE
      }
      FILLVALUE {
         FILL_TIME H5D_FILL_TIME_ALLOC
         VALUE  0
      }
      ALLOCATION_TIME {
         H5D_ALLOC_TIME_INCR
      }
   }
}
}

Compressing with blosc and h5repack

For a test you might want to try to compress a raw, uncompressed data file from an experiment in order to get an idea of what level of compression can be achieved:

The input data is an uncompressed 3D stack of images in a chunked dataset:

h5dump -pH input.h5 
HDF5 "input.h5" {
GROUP "/" {
   DATASET "data" {
      DATATYPE  H5T_STD_U16LE
      DATASPACE  SIMPLE { ( 100, 1536, 2048 ) / ( H5S_UNLIMITED, 1536, 2048 ) }
      STORAGE_LAYOUT {
         CHUNKED ( 1, 1536, 2048 )
         SIZE 629145600
      }
      FILTERS {
         NONE
      }
      FILLVALUE {
         FILL_TIME H5D_FILL_TIME_IFSET
         VALUE  0
      }
      ALLOCATION_TIME {
         H5D_ALLOC_TIME_INCR
      }
   }
}
}

Compress and check the output file.

Note that 32001 is the Blosc User Defined (UD) filter code:

export HDF5_PLUGIN_PATH=/dls_sw/prod/tools/RHEL7-x86_64/hdf5filters/0-6-1/prefix/avx2-hdf5_1.10/h5plugin
h5repack -L -f UD=32001,0,7,0,0,0,0,1,1,1 input.h5 out.h5
h5dump -pH out.h5 
HDF5 "out.h5" {
GROUP "/" {
   DATASET "data" {
      DATATYPE  H5T_STD_U16LE
      DATASPACE  SIMPLE { ( 100, 1536, 2048 ) / ( H5S_UNLIMITED, 1536, 2048 ) }
      STORAGE_LAYOUT {
         CHUNKED ( 1, 1536, 2048 )
         SIZE 8839621 (71.173:1 COMPRESSION)       <== decent compression ratio
      }
      FILTERS {
         USER_DEFINED_FILTER {
            FILTER_ID 32001
            COMMENT blosc
            PARAMS { 2 2 2 6291456 1 1 1 }        <== blosc filter parameters
         }
      }
      FILLVALUE {
         FILL_TIME H5D_FILL_TIME_IFSET
         VALUE  0
      }
      ALLOCATION_TIME {
         H5D_ALLOC_TIME_INCR
      }
   }
}
}