Store
editStore
editThe store module allows you to control how index data is stored and accessed on disk.
This is a low-level setting. Some store implementations have poor concurrency or disable optimizations for heap memory usage. We recommend sticking to the defaults.
File system storage types
editThere are different file system implementations or storage types. By default, Elasticsearch will pick the best implementation based on the operating environment.
The storage type can also be explicitly set for all indices by configuring the
store type in the config/elasticsearch.yml
file:
index.store.type: hybridfs
It is a static setting that can be set on a per-index basis at index creation time:
response = client.indices.create( index: 'my-index-000001', body: { settings: { 'index.store.type' => 'hybridfs' } } ) puts response
PUT /my-index-000001 { "settings": { "index.store.type": "hybridfs" } }
This is an expert-only setting and may be removed in the future.
The following sections lists all the different storage types supported.
-
fs
-
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. -
simplefs
- deprecated::[7.15,"simplefs is deprecated and will be removed in 8.0. Use niofs or other file systems instead. Elasticsearch 7.15 or later uses niofs for the simplefs store type as it offers superior or equivalent performance to simplefs."]
The Simple FS type is a straightforward implementation of file system
storage (maps to Lucene SimpleFsDirectory
) using a random access file.
This implementation has poor concurrent performance (multiple threads
will bottleneck) and disables some optimizations for heap memory usage.
-
niofs
-
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. -
mmapfs
-
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. -
hybridfs
-
The
hybridfs
type is a hybrid ofniofs
andmmapfs
, 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 LuceneNIOFSDirectory
. Similarly tommapfs
be sure you have allowed plenty of virtual address space.
You can restrict the use of the mmapfs
and the related hybridfs
store type
via the setting node.store.allow_mmap
. This is a boolean setting indicating
whether or not memory-mapping is allowed. The default is to allow it. This
setting is useful, for example, if you are in an environment where you can not
control the ability to create a lot of memory maps so you need disable the
ability to use memory-mapping.