does setting HEAP_NEWSIZE=“800M” mean young generation can only use 800M?
> On Jun 13, 2018, at 12:51 PM, Steinmaurer, Thomas > <thomas.steinmau...@dynatrace.com> wrote: > > Explicitly setting Xmn with G1 basically results in <>overriding the target > pause-time goal, thus should be avoided. > http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html > <http://www.oracle.com/technetwork/articles/java/g1gc-1984535.html> > > Thomas > > > From: rajpal reddy [mailto:rajpalreddy...@gmail.com > <mailto:rajpalreddy...@gmail.com>] > Sent: Mittwoch, 13. Juni 2018 17:27 > To: user@cassandra.apache.org <mailto:user@cassandra.apache.org> > Subject: Re: G1GC CPU Spike > > we have this has the Heap settings . is the HEAP_NEWSIZE is required only for > CMS. can we get rid of that for G1GC so that it can be used? > MAX_HEAP_SIZE="8192M" > HEAP_NEWSIZE=“800M" > > On Jun 13, 2018, at 11:15 AM, Chris Lohfink <clohf...@apple.com > <mailto:clohf...@apple.com>> wrote: > > That metric is the total number of seconds spent in GC, it will increase over > time with every young gc which is expected. Whats interesting is the rate of > growth not the fact that its increasing. If graphing tool has option to graph > derivative you should use that instead. > > Chris > > > On Jun 13, 2018, at 9:51 AM, rajpal reddy <rajpalreddy...@gmail.com > <mailto:rajpalreddy...@gmail.com>> wrote: > > jvm_gc_collection_seconds_count{gc="G1 Young Generation”} and also young > generation seconds count keep increasing > > <PastedGraphic-1.png> > > On Jun 13, 2018, at 9:52 AM, Chris Lohfink <clohf...@apple.com > <mailto:clohf...@apple.com>> wrote: > > The gc log file is best to share when asking for help with tuning. The top of > file has all the computed args it ran with and it gives details on what part > of the GC is taking time. I would guess the CPU spike is from full GCs which > with that small heap of a heap is probably from evacuation failures. > Reserving more of the heap to be free (-XX:G1ReservePercent=25) can help, > along with increasing the amount of heap. 8GB is pretty small for G1, might > be better off with CMS. > > Chris > > > On Jun 13, 2018, at 8:42 AM, rajpal reddy <rajpalreddy...@gmail.com > <mailto:rajpalreddy...@gmail.com>> wrote: > > Hello, > > we are using G1GC and noticing garbage collection taking a while and during > that process we are seeing cpu spiking up to 70-80%. can you please let us > know. if we have to tune any parameters for that. attaching the cassandra-env > file with jam-options.<cassandra-env.txt> > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org > <mailto:user-unsubscr...@cassandra.apache.org> > For additional commands, e-mail: user-h...@cassandra.apache.org > <mailto:user-h...@cassandra.apache.org> > > > --------------------------------------------------------------------- > To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org > <mailto:user-unsubscr...@cassandra.apache.org> > For additional commands, e-mail: user-h...@cassandra.apache.org > <mailto:user-h...@cassandra.apache.org> > > > > The contents of this e-mail are intended for the named addressee only. It > contains information that may be confidential. Unless you are the named > addressee or an authorized designee, you may not copy or use it, or disclose > it to anyone else. If you received it in error please notify us immediately > and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) > is a company registered in Linz whose registered office is at 4040 Linz, > Austria, Freistädterstraße 313
