We are facing frequent issues with WSO2 APIM – 3.1.0 & IS – 5.10.0. Please find the below error message in the logs:

2024-07-21T23:57:18,620 [-] [PassThrough HTTPS-Listener I/O dispatcher Listener] WARN PassThroughHttpMultiSSLListener System may be unstable: HTTPS ListeningIOReactor encountered a checked exception : Too many open files
java.io.IOException: Too many open files
at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) ~[?:1.8.0_281]
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:424) ~[?:1.8.0_281]
at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:252) ~[?:1.8.0_281]
at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvent(DefaultListeningIOReactor.java:170) [httpcore-nio_4.3.3.wso2v4.jar:?]
at org.apache.http.impl.nio.reactor.DefaultListeningIOReactor.processEvents(DefaultListeningIOReactor.java:153) [httpcore-nio_4.3.3.wso2v4.jar:?]
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor.execute(AbstractMultiworkerIOReactor.java:349) [httpcore-nio_4.3.3.wso2v4.jar:?]
at org.apache.synapse.transport.passthru.core.PassThroughListeningIOReactorManager$1.run(PassThroughListeningIOReactorManager.java:536) [synapse-nhttp-transport_2.1.7.wso2v147.jar:?]
at java.lang.Thread.run(Thread.java:748) [?:1.8.0_281]

As per recommendations, we increased the soft limit to 65535 but still face the same issue. As per analysis, the application opens 1,000 to 1,500 files per hour and closes 2 to 3. This is forcing us to restart services every three days.

Some of the system parameters are as below:

file-max value is 2097152
Soft limit and Hard limit 65535
Soft Proc and Hard Proc 20000
JVM – -Xms4096m -Xmx4096m -XX:MaxPermSize=1024m

Any assistance would be of great help. Thank you!

Increased the soft limit