Here are the new settings we are trying out. They seemed to "help" with
cass. In the end I assume we will need a script to do rolling restarts or
better yet hbase does it on its own!!
Thanks for the help!
-XX:+UseCMSInitiatingOccupancyOnly
-XX:CMSInitiatingOccupancyFraction=60
-XX:+CMSParallelRemarkEnabled
-XX:SurvivorRatio=8
-XX:NewRatio=3
-XX:MaxTenuringThreshold=1
On Mon, Jan 3, 2011 at 5:05 PM, Stack <[email protected]> wrote:
> On Mon, Jan 3, 2011 at 12:50 PM, Wayne <[email protected]> wrote:
> > We have an 8GB heap. What should newsize be? I just had another node die
> > hard after going into a CMF storm. I swear it had solid CMFs 30+ in a
> row.
> >
>
> Did a full stop-the-world GC run in between? It should have cleaned
> up fragmentation.
>
> > I have no idea what eden space is or how to see what it is. ??
> >
>
> Sorry. There's a bunch of 'cute' terms used for describing the two
> heap areas in the JVM. Basically, new stuff goes into the 'new' or
> 'eden' area first. If it sticks around through N (configurable) GCs,
> it gets promoted to old or tenured generation (there are other names
> for these notions of young and old). The garbage collection
> algorithms done in the two heaps differ. See the Ted citation for
> more on the gruesome details (though come up to a newer version of
> that doc). The JVM is supposed to work ergonomically but it just
> ain't smart enough dealing w/ HBase/Cass loadings it seems (e.g. it
> keeps growing the new/eden space pathologically it would seem).
>
>
> > Not knowing what else to do I will start using some of the Cassandra
> > settings I used to improve it by setting the occupancy fraction. Any
> other
> > ideas???
> >
>
> Which config. you talking of? -XX:+CMSInitiatingOccupancyFraction?
> Thats a good one to toggle down from defaullts. Should help put off
> promotion failures a while.
>
>
> St.Ack
>
