Default file system implementation. This will pick the best implementation
depending on the operating environment, which is currently hybridfs on all
supported systems but is subject to change.
The NIO FS type stores the shard index on the file system (maps to Lucene
NIOFSDirectory) using NIO. It allows multiple threads to read from the same
file concurrently. It is not recommended on Windows because of a bug in the
SUN Java implementation and disables some optimizations for heap memory
usage.
The MMap FS type stores the shard index on the file system (maps to Lucene
MMapDirectory) by mapping a file into memory (mmap). Memory mapping uses up a
portion of the virtual memory address space in your process equal to the size
of the file being mapped. Before using this class, be sure you have allowed
plenty of virtual address space.
The hybridfs type is a hybrid of niofs and mmapfs, which chooses the best
file system type for each type of file based on the read access pattern.
Currently only the Lucene term dictionary, norms and doc values files are
memory mapped. All other files are opened using Lucene NIOFSDirectory.
Similarly to mmapfs be sure you have allowed plenty of virtual address space.
Returns the enum constant of this class with the specified name.
The string must match exactly an identifier used to declare an
enum constant in this class. (Extraneous whitespace characters are
not permitted.)
Parameters:
name - the name of the enum constant to be returned.