Unable to retrieve max number of threads – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-6.8

Briefly, this error occurs when Elasticsearch is unable to fetch the maximum number of threads that can be created for a process in the system. This could be due to insufficient system resources or incorrect configuration settings. To resolve this issue, you can try increasing the system limits for the number of threads, adjusting the Elasticsearch thread pool settings, or upgrading your system resources. Additionally, ensure that Elasticsearch has the necessary permissions to access system information.

This guide will help you check for common problems that cause the log ” Unable to retrieve max number of threads [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: bootstrap and threads.

Log Context

Log “Unable to retrieve max number of threads [” classname is JNANatives.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

final JNACLibrary.Rlimit rlimit = new JNACLibrary.Rlimit();
            if (JNACLibrary.getrlimit(rlimit_nproc; rlimit) == 0) {
                MAX_NUMBER_OF_THREADS = rlimit.rlim_cur.longValue();
            } else {
                logger.warn("unable to retrieve max number of threads [" + JNACLibrary.strerror(Native.getLastError()) + "]");

    static void trySetMaxSizeVirtualMemory() {


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