Resurfaced "java.io.IOException: Too many open files" when hit by multiple requests issue

[tomassommar]

This has previously been reported in issue 1578: #1578

The issue was set as resolved in 4.0.2.Final, but now exists in 4.0.6.Final.

Do you have any advice on this issue?

[lw346]

Is the error being logged in an exceptionCaught, or is it causing the server to crash? Do you have a stacktrace?

[tomassommar]

Yes, the error is logged in an exceptionCaught. It is not causing the server to crash, but the request to not to be processed.

Stack trace:

2013-08-12 06:36:31 WARN  DefaultChannelPipeline:953 - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.io.IOException: Too many open files
        at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
        at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:152)
        at io.netty.channel.socket.nio.NioServerSocketChannel.doReadMessages(NioServerSocketChannel.java:111)
        at io.netty.channel.nio.AbstractNioMessageChannel$NioMessageUnsafe.read(AbstractNioMessageChannel.java:70)
        at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:497)
        at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:465)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:359)
        at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:101)
        at java.lang.Thread.run(Thread.java:662)

If the request can't be processed (or queued for later processing), a suggestion is to instead throw an exception signaling a HTTP 503 Service Unavailable response.

[lw346]

This is expected behaviour, and is nothing that can be changed. The JVM is signalling that it is unable to accept the channel - therefore no connection can be initiated and no response can be sent. The client will see a connection failure. If you have a load-balancer, it should retry against an alternate host, or return the 503 on your application's behalf.

[johnwonder]

i have this issue now ,