WARNING: Version 5.1 of Elasticsearch has passed its EOL date.
This documentation is no longer being maintained and may be removed. If you are running this version, we strongly advise you to upgrade. For the latest information, see the current release documentation.
Only a subset of index files were open with
mmap on Elasticsearch 2.x. As of
Elasticsearch 5.0, all index files will be open with
mmap on 64-bit systems.
While this may increase the amount of virtual memory used by Elasticsearch,
there is nothing to worry about since this is only address space consumption
and the actual memory usage of Elasticsearch will stay similar to what it was
in 2.x. See http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html
for more information.