73 lines
2.4 KiB
Plaintext
73 lines
2.4 KiB
Plaintext
[[index-modules-store]]
|
|
== Store
|
|
|
|
The store module allows you to control how index data is stored and accessed on disk.
|
|
|
|
[float]
|
|
[[file-system]]
|
|
=== File system storage types
|
|
|
|
There are different file system implementations or _storage types_. The best
|
|
one for the operating environment will be automatically chosen: `mmapfs` on
|
|
Windows 64bit, `simplefs` on Windows 32bit, and `default` (hybrid `niofs` and
|
|
`mmapfs`) for the rest.
|
|
|
|
This can be overridden for all indices by adding this to the
|
|
`config/elasticsearch.yml` file:
|
|
|
|
[source,yaml]
|
|
---------------------------------
|
|
index.store.type: niofs
|
|
---------------------------------
|
|
|
|
It is a _static_ setting that can be set on a per-index basis at index
|
|
creation time:
|
|
|
|
[source,js]
|
|
---------------------------------
|
|
PUT /my_index
|
|
{
|
|
"settings": {
|
|
"index.store.type": "niofs"
|
|
}
|
|
}
|
|
---------------------------------
|
|
|
|
experimental[This is an expert-only setting and may be removed in the future]
|
|
|
|
The following sections lists all the different storage types supported.
|
|
|
|
[[simplefs]]`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). It is usually better to use the `niofs` when you need
|
|
index persistence.
|
|
|
|
[[niofs]]`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.
|
|
|
|
[[mmapfs]]`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
|
|
<<vm-max-map-count,virtual address space>>.
|
|
|
|
[[default_fs]]`default_fs`::
|
|
|
|
The `default` type is a hybrid of NIO FS and MMapFS, which chooses the best
|
|
file system for each type of file. Currently only the Lucene term dictionary
|
|
and doc values files are memory mapped to reduce the impact on the operating
|
|
system. All other files are opened using Lucene `NIOFSDirectory`. Address
|
|
space settings (<<vm-max-map-count>>) might also apply if your term
|
|
dictionaries are large.
|
|
|