Netcdf-java System Properties

The netcdf-java library defines several Java System Properties for runtime configuration:

Key Meaning Default Value Where Used
“unidata.h5iosp.inflate.buffersize” used by the h5iosp when uncompressing a file 512 Bytes ucar.nc2.iosp.hdf5.H5tiledLayoutBB
“nj22.cache” Set the root directory for the cache user.home or user.dir + “/.unidata/cache/” ucar.nc1.util.DiskCache
“nj22.cachePolicy” Create the file in the cache directory Create the file in the same directory as the original ucar.nc1.util.DiskCache
“nj22.cache” Set the root directory for the cache user.home or user.dir + “/.unidata/cache/” ucar.nc1.util.DiskCache2
“nj22.cachePersistRoot” Set the root directory for the cache user.home or user.dir + “/” ucar.nc1.util.DiskCache2
“ucar.unidata.io.http.httpBufferSize” The buffer size when reading over http 262144 (256 KiB) ucar.unidata.io.http.HttpRandomAccessFile
“ucar.unidata.io.http.maxHttpBufferSize” Deprecated. Use “ucar.unidata.io.http.httpBufferSize”. 262144 (256 KiB) ucar.unidata.io.http.HttpRandomAccessFile
“ucar.unidata.io.http.maxReadCacheSize” The read cache size in bytes 10485760 (10 MiB) ucar.unidata.io.http.HttpRandomAccessFile
“httpservices.urlencode” encode the url passed to the HTTPMethod constructor true ucar.httpservices.HTTPMethod
“store” key store path None ucar.httpservices.HTTPSession
“storepassword” key store password None ucar.httpservices.HTTPSession
“tdsmonitor.datadir” Path to local log storage user.home thredds.ui.monitor.LocalManager.java

S3 specific properties

When reading from an AWS S3 Object store, the following properties can be set to control the behavior of ucar.unidata.io.s3.S3RandomAccessFile

Key Meaning Default Value
“ucar.unidata.io.s3.bufferSize” The S3 reading buffer size in bytes 262144 (256 KiB)
“ucar.unidata.io.s3.maxReadCacheSize” The read cache size in bytes 10485760 (10 MiB)
“ucar.unidata.io.s3.httpMaxConnections” The maximum number of connections allowed in the S3 http connection pool 128
“ucar.unidata.io.s3.connectionTimeout” The amount of time in milliseconds to wait when initially establishing a connection 100000
“ucar.unidata.io.s3.socketTimeout” The amount of time in milliseconds to wait for data to be transferred 100000