You may run into this bug https://issues.apache.org/jira/browse/KAFKA-4614
On Thu, 12 Jan 2017 at 23:38 Stephen Powis <spo...@salesforce.com> wrote: > Per my email to the list in Sept, when I reviewed GC logs then, I didn't > see anything out of the ordinary. ( > > http://mail-archives.apache.org/mod_mbox/kafka-users/201609.mbox/%3CCABQB-gS7h4Nuq3TKgHoAVeRHPWnBNs2B0Tz0kCjmdB9c0SDcLQ%40mail.gmail.com%3E > ) > > Reviewing the GC logs from this morning around the timestamp in my previous > email, I see GC running roughly every 10-12 seconds, with total times > similar to the following: > > 2017-01-12T07:16:46.867-0500: 46891.844: Total time for which application > > threads were stopped: 0.0141281 seconds, Stopping threads took: 0.0002171 > > seconds > > > > > Here is a link to a GCEasy report: > > http://gceasy.io/my-gc-report.jsp?p=c2hhcmVkLzIwMTcvMDEvMTIvLS10b3RhbEdDLWthZmthMS00LmxvZy5nei0tMTUtMzQtNTk= > > > Currently using G1 gc with the following settings: > > -Xmx12G -Xms12G -server -XX:MaxPermSize=48M -verbose:gc > -Xloggc:/var/log/kafka/gc.log -XX:+PrintGCDateStamps -XX:+PrintGCDetails > -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime > -XX:+PrintTLAB -XX:+DisableExplicitGC -XX:+UseGCLogFileRotation > -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=100M -XX:+UseCompressedOops > -XX:+AlwaysPreTouch -XX:+UseG1GC -XX:MaxGCPauseMillis=20 > -XX:+HeapDumpOnOutOfMemoryError > -XX:HeapDumpPath=/var/log/kafka/heapDump.log > -Xloggc:/opt/kafka/current/bin/../logs/kafkaServer-gc.log -verbose:gc > -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintGCTimeStamps > > > > On Thu, Jan 12, 2017 at 9:55 AM, Tauzell, Dave < > dave.tauz...@surescripts.com > > wrote: > > > Can you collect garbage collection stats and verify there isn't a long GC > > happening at the same time? > > > > -Dave > > > > -----Original Message----- > > From: Stephen Powis [mailto:spo...@salesforce.com] > > Sent: Thursday, January 12, 2017 8:34 AM > > To: users@kafka.apache.org > > Subject: Re: Taking a long time to roll a new log segment (~1 min) > > > > So per the kafka docs I up'd our FD limit to 100k, and we are no longer > > seeing the process die, which is good. > > > > Unfortunately we're still seeing very high log segment roll times, and > I'm > > unsure if this is considered 'normal', as it tends to block producers > > during this period. > > > > We are running kafka 0.10.0.1, but I patched in some additionally timing > > statements into the kafka.log.log roll() method to narrow down exactly > > which part of that method is taking so long. > > > > Again, typically the process to roll a new log file takes only 1-2ms > tops, > > but several times a day it takes 30-60+ seconds, across all of our > > brokers. I've narrowed it down to this bit of code causing the issue: > > https://github.com/apache/kafka/blob/0.10.0/core/src/ > > main/scala/kafka/log/Log.scala#L652-L658 > > > > Here's an example of output w/ my additional timing log statements: > > > > [2017-01-12 07:17:58,199] INFO Rolled new log segment for 'MyTopic-4' in > > > 28028 ms. (kafka.log.Log) > > > > [2017-01-12 07:17:58,200] INFO LastEntry match time 'EventStream-4' in > > > 28027 ms. (kafka.log.Log) > > > > > > > Any thoughts? Help? This considered normal? > > > > Thanks > > Stephen > > > > > > On Tue, Jan 10, 2017 at 2:37 AM, Ewen Cheslack-Postava < > e...@confluent.io> > > wrote: > > > > > I can't speak to the exact details of why fds would be kept open > > > longer in that specific case, but are you aware that the > > > recommendation for production clusters for open fd limits is much > > > higher? It's been suggested to be 100,000 as a starting point for quite > > awhile: > > > http://kafka.apache.org/documentation.html#os > > > > > > -Ewen > > > > > > On Mon, Jan 9, 2017 at 12:45 PM, Stephen Powis <spo...@salesforce.com> > > > wrote: > > > > > > > Hey! > > > > > > > > I've run into something concerning in our production cluster....I > > > > believe I've posted this question to the mailing list previously ( > > > > http://mail-archives.apache.org/mod_mbox/kafka-users/201609.mbox/bro > > > > wser > > > ) > > > > but the problem has become considerably more serious. > > > > > > > > We've been fighting issues where Kafka 0.10.0.1 hits its max file > > > > descriptor limit. Our limit is set to ~16k, and under normal > > > > operation > > > it > > > > holds steady around 4k open files. > > > > > > > > But occasionally Kafka will roll a new log segment, which typically > > > > takes on the order of magnitude of a few milliseconds. > > > > However...sometimes it will take a considerable amount of time, any > > > > where from 40 seconds up to over a minute. When this happens, it > > > > seems like connections are not released by kafka, and we end up with > > > > thousands of client connections > > > stuck > > > > in CLOSE_WAIT, which pile up and exceed our max file descriptor > limit. > > > > This happens all in the span of about a minute. > > > > > > > > Our logs look like this: > > > > > > > > [2017-01-08 01:10:17,117] INFO Rolled new log segment for > > > > 'MyTopic-8' in > > > > > 41122 ms. (kafka.log.Log) > > > > > [2017-01-08 01:10:32,550] INFO Rolled new log segment for > 'MyTopic-4' > > > in > > > > 1 > > > > > ms. (kafka.log.Log) > > > > > [2017-01-08 01:11:10,039] INFO [Group Metadata Manager on Broker > 4]: > > > > > Removed 0 expired offsets in 0 milliseconds. > > > > > (kafka.coordinator.GroupMetadataManager) > > > > > [2017-01-08 01:19:02,877] ERROR Error while accepting connection > > > > > (kafka.network.Acceptor) > > > > > java.io.IOException: Too many open files at > > > > > sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method) > > > > > > > > > at > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( > > > ServerSocketChannelImpl.java: > > > > 422) > > > > > at > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( > > > ServerSocketChannelImpl.java: > > > > 250) > > > > > at kafka.network.Acceptor.accept(SocketServer.scala:323) > > > > > at kafka.network.Acceptor.run(SocketServer.scala:268) > > > > > at java.lang.Thread.run(Thread.java:745) > > > > > [2017-01-08 01:19:02,877] ERROR Error while accepting connection > > > > > (kafka.network.Acceptor) > > > > > java.io.IOException: Too many open files > > > > > at sun.nio.ch.ServerSocketChannelImpl.accept0(Native > Method) > > > > > at > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( > > > ServerSocketChannelImpl.java: > > > > 422) > > > > > at > > > > > sun.nio.ch.ServerSocketChannelImpl.accept( > > > ServerSocketChannelImpl.java: > > > > 250) > > > > > at kafka.network.Acceptor.accept(SocketServer.scala:323) > > > > > at kafka.network.Acceptor.run(SocketServer.scala:268) > > > > > at java.lang.Thread.run(Thread.java:745) > > > > > ..... > > > > > > > > > > > > > > > > > And then kafka crashes. > > > > > > > > Has anyone seen this behavior of slow log segmented being rolled? > > > > Any ideas of how to track down what could be causing this? > > > > > > > > Thanks! > > > > Stephen > > > > > > > > > This e-mail and any files transmitted with it are confidential, may > > contain sensitive information, and are intended solely for the use of the > > individual or entity to whom they are addressed. If you have received > this > > e-mail in error, please notify the sender by reply e-mail immediately and > > destroy all copies of the e-mail and any attachments. > > >
