I don't think there's many folks using G1 in production for HBase yet. Out of curiosity, what JVM and version are you using? I heard G1 got much better somewhere after 1.7u60, though I don't have personal experience with it.
On Tuesday, January 6, 2015, Shuai Lin <[email protected]> wrote: > Cool, how can I get a graph like that? > > On Wed, Jan 7, 2015 at 4:06 AM, Otis Gospodnetic < > [email protected] <javascript:;> > > wrote: > > > Hi, > > > > The first thing I'd want to know is which memory poor is getting filled. > > There are several in the JVM. > > Here's an example: https://apps.sematext.com/spm-reports/s/kZgBWLsJRd > > (this > > one is actually from an HBase cluster). If you see any of the lines at > > 100% that's potential trouble. If it stays at 100% it's trouble (i.e. > OOM > > about to happen). If it's constantly close to 100% that's OOM waiting to > > happen and you should check your GC and CPU graphs and see how much time > > the JVM is spending on GC. > > > > Once you know which pool is problematic you'll be better informed and may > > be able to increase the size of just that pool. > > > > Otis > > -- > > Monitoring * Alerting * Anomaly Detection * Centralized Log Management > > Solr & Elasticsearch Support * http://sematext.com/ > > > > > > On Tue, Jan 6, 2015 at 6:32 AM, Shuai Lin <[email protected] > <javascript:;>> wrote: > > > > > Hi all, > > > > > > We have a hbase cluster of 5 region servers, each, each hosting 60+ > > > regions. > > > > > > But under heavy load the region servers crashes for OOME now and then: > > > > > > # > > > # java.lang.OutOfMemoryError: Java heap space > > > # -XX:OnOutOfMemoryError="kill -9 %p" > > > # Executing /bin/sh -c "kill -9 16820"... > > > > > > We have max heap size set to 22GB (-Xmx22528m) for each RS, and uses > the > > > G1GC (-XX:+UseG1GC). To debug the problem we have turned on the jvm GC > > > log. The last few lines of the GC log before each crash are always > like > > > this: > > > > > > 2015-01-06T11:10:19.087+0000: 5035.720: [Full GC 7122M->5837M(21G), > > > 0.8867660 secs] > > > [Eden: 1024.0K(7278.0M)->0.0B(8139.0M) Survivors: 68.0M->0.0B Heap: > > > 7122.7M(22.0G)->5837.2M(22.0G)] > > > [Times: user=1.42 sys=0.00, real=0.89 secs] > > > 2015-01-06T11:10:19.976+0000: 5036.608: [Full GC 5837M->5836M(21G), > > > 0.6378260 secs] > > > [Eden: 0.0B(8139.0M)->0.0B(8139.0M) Survivors: 0.0B->0.0B Heap: > > > 5837.2M(22.0G)->5836.5M(22.0G)] > > > [Times: user=0.93 sys=0.00, real=0.63 secs] > > > > > > From the last lineI see the heap only occupies 5837MB, and the capacity > > is > > > 22GB, so how can the OOM happen? Or is my interpretation of the gc log > > > wrong? > > > > > > I read some articles and onlhy got some basic concept of G1GC. I've > tried > > > tools like GCViewer, but none gives me useful explanation of the > details > > of > > > the GC log. > > > > > > > > > Regards, > > > Shuai > > > > > >
