Could you also check if the on-disk data size/rate match the network traffic?
Thanks, Jun On Thu, Feb 6, 2014 at 7:48 PM, Carl Lerche <m...@carllerche.com> wrote: > So, the "good news" is that the problem came back again. The bad news > is that I disabled debug logs as it was filling disk (and I had other > fires to put out). I will re-enable debug logs and wait for it to > happen again. > > On Thu, Feb 6, 2014 at 4:05 AM, Neha Narkhede <neha.narkh...@gmail.com> > wrote: > > Carl, > > > > It will help if you can list the steps to reproduce this issue starting > > from a fresh installation. Your setup, the way it stands, seems to have > > gone through some config and state changes. > > > > Thanks, > > Neha > > > > > > On Wed, Feb 5, 2014 at 5:17 PM, Joel Koshy <jjkosh...@gmail.com> wrote: > > > >> On Wed, Feb 05, 2014 at 04:51:16PM -0800, Carl Lerche wrote: > >> > So, I tried enabling debug logging, I also made some tweaks to the > >> > config (which I probably shouldn't have) and craziness happened. > >> > > >> > First, some more context. Besides the very high network traffic, we > >> > were seeing some other issues that we were not focusing on yet. > >> > > >> > * Even though the log retention was set to 50GB & 24 hours, data logs > >> > were getting cleaned up far quicker quicker. I'm not entirely sure how > >> > much quicker, but there was definitely far less than 12 hours and 1GB > >> > of data. > >> > > >> > * Kafka was not properly balanced. We had 3 servers, and only 2 of > >> > them were partition leaders. One server was a replica for all > >> > partitions. We tried to run a rebalance command, but it did not work. > >> > We were going to investigate later. > >> > >> Were any of the brokers down for an extended period? If the preferred > >> replica election command failed it could be because the preferred > >> replica was catching up (which could explain the higher than expected > >> network traffic). Do you monitor the under-replicated partitions count > >> on your cluster? If you have that data it could help confirm this. > >> > >> Joel > >> > >> > > >> > So, after restarting all the kafkas, something happened with the > >> > offsets. The offsets that our consumers had no longer existed. It > >> > looks like somehow all the contents was lost? The logs show many > >> > exceptions like: > >> > > >> > `Request for offset 770354 but we only have log segments in the range > >> > 759234 to 759838.` > >> > > >> > So, I reset all the consumer offsets to the head of the queue as I did > >> > not know of anything better to do. Once the dust settled, all the > >> > issues we were seeing vanished. Communication between Kafka nodes > >> > appear to be normal, Kafka was able to rebalance, and hopefully log > >> > retention will be normal. > >> > > >> > I am unsure what happened or how to get more debug information. > >> > > >> > On Wed, Feb 5, 2014 at 12:31 PM, Jay Kreps <jay.kr...@gmail.com> > wrote: > >> > > Can you enable DEBUG logging in log4j and see what requests are > coming > >> in? > >> > > > >> > > -Jay > >> > > > >> > > > >> > > On Tue, Feb 4, 2014 at 9:51 PM, Carl Lerche <m...@carllerche.com> > wrote: > >> > > > >> > >> Hi Jay, > >> > >> > >> > >> I do not believe that I have changed the replica.fetch.wait.max.ms > >> > >> setting. Here I have included the kafka config as well as a > snapshot > >> > >> of jnettop from one of the servers. > >> > >> > >> > >> https://gist.github.com/carllerche/4f2cf0f0f6d1e891f482 > >> > >> > >> > >> The bottom row (89.9K/s) is the producer (it lives on a Kafka > server). > >> > >> The top two rows are Kafkas on other servers, you can see the > combined > >> > >> throughput is ~80MB/s > >> > >> > >> > >> On Tue, Feb 4, 2014 at 9:36 PM, Jay Kreps <jay.kr...@gmail.com> > >> wrote: > >> > >> > No this is not normal. > >> > >> > > >> > >> > Checking twice a second (using 500ms default) for new data > shouldn't > >> > >> cause > >> > >> > high network traffic (that should be like < 1KB of overhead). I > >> don't > >> > >> think > >> > >> > that explains things. Is it possible that setting has been > >> overridden? > >> > >> > > >> > >> > -Jay > >> > >> > > >> > >> > > >> > >> > On Tue, Feb 4, 2014 at 9:25 PM, Guozhang Wang < > wangg...@gmail.com> > >> > >> wrote: > >> > >> > > >> > >> >> Hi Carl, > >> > >> >> > >> > >> >> For each partition the follower will also fetch data from the > >> leader > >> > >> >> replica, even if there is no new data in the leader replicas. > >> > >> >> > >> > >> >> One thing you can try to increase replica.fetch.wait.max.ms > (default > >> > >> value > >> > >> >> 500ms) so that the followers's fetching request frequency to the > >> leader > >> > >> can > >> > >> >> be reduced, and see if that has some effect on the traffic. > >> > >> >> > >> > >> >> Guozhang > >> > >> >> > >> > >> >> > >> > >> >> On Tue, Feb 4, 2014 at 8:46 PM, Carl Lerche <m...@carllerche.com> > >> wrote: > >> > >> >> > >> > >> >> > Hello, > >> > >> >> > > >> > >> >> > I'm running a 0.8.0 Kafka cluster of 3 servers. The service > that > >> it is > >> > >> >> > for is not in full production yet, so the data written to > >> cluster is > >> > >> >> > minimal (seems to average between 100kb/s -> 300kb/s per > >> server). I > >> > >> >> > have configured Kafka to have a 3 replicas. I am noticing that > >> each > >> > >> >> > Kafka server is talking to all the others at a data rate of > >> 40MB/s for > >> > >> >> > each server (so, a total of 80MB/s for each server). This > >> > >> >> > communication is constant. > >> > >> >> > > >> > >> >> > Is this normal? This seems like very strange behavior and I'm > not > >> > >> >> > exactly sure how to debug. > >> > >> >> > > >> > >> >> > Thanks, > >> > >> >> > Carl > >> > >> >> > > >> > >> >> > >> > >> >> > >> > >> >> > >> > >> >> -- > >> > >> >> -- Guozhang > >> > >> >> > >> > >> > >> > >> >
