« File Descriptors Number of threads »
Elastic Docs ›Elasticsearch Guide [8.19] ›Set up Elasticsearch ›Important system configuration

Virtual memory

edit
IMPORTANT: This documentation is no longer updated. Refer to Elastic's version policy and the latest documentation.

Virtual memory

edit

Elasticsearch uses a mmapfs directory by default to store its indices. The default operating system limits on mmap counts is likely to be too low, which might result in out of memory exceptions.

If the operating system’s default vm.max_map_count value is 1048576 or higher, no configuration change is necessary. If the default value is lower than 1048576, configure the vm.max_map_count parameter to 1048576.

On Linux, you can increase the limits by running the following command as root:

sysctl -w vm.max_map_count=1048576

To set this value permanently, update the vm.max_map_count setting in /etc/sysctl.conf. To verify after rebooting, run sysctl vm.max_map_count.

The RPM and Debian packages will configure this setting automatically. No further configuration is required.

You can find out the current mmap count of a running Elasticsearch process using the following command, where $PID is the process ID of the running Elasticsearch process:

wc -l /proc/$PID/maps
« File Descriptors Number of threads »