On 1/17/11, Dan Hendry wrote:
> Since applying these settings, the one time I saw the same type of behavior
> as before, the following appeared in the GC log.
>
>(concurrent mode failure): 9418431K->6267709K(11841536K), 26.4973750
> secs] 9777393K->6267709K(12290944K), [CMS Perm : 20477K->2044
> Now, a full stop of the application was what I was seeing extensively before
> (100-200 times over the course of a major compaction as reported by
> gossipers on other nodes). I have also just noticed that the previous
> instability (ie application stops) correlated with the compaction of a few
>
Thanks, Dan:
Yes, -Xmn512MB/1G sizes the Young Generation explicitly and removes the
adaptive resizing out of the picture. (If at all possible send your gc log
over & we can analyze the promotion failure a little bit more finely.)
The low load implies that that you are able to use the parallel thr
Thanks for all the info, I think I have been able to sort out my issue. The
new settings I am using are:
-Xmn512M (Very important I think)
-XX:SurvivorRatio=5 (Not very important I think)
-XX:MaxTenuringThreshold=5
-XX:ParallelGCThreads=8
-XX:CMSInitiatingOccupancyFraction=75
Since applying these
On Mon, Jan 17, 2011 at 11:58 AM, Peter Schuller
wrote:
> 45 seconds is pretty significant even for a 12 gig heap
Note that you really need to uncomment the -XX:PrintGC* arguments to
get a detailed GC log from the jvm before taking guesses at this; the
numbers GCInspector can get are NOT pause ti
> very quickly from the young generation to the old generation". Furthermore,
> the CMSInitiatingOccupancyFraction of 75 (from a JVM default of 68) means
> "start gc in the old generation later", presumably to allow Cassandra to use
> more of the old generation heap without needlessly trying to fre
Dan,
Please kindly attach your:
1) java -version
2) full commandline settings, heap sizes.
3) gc log from one of the nodes via:
-XX:+PrintTenuringDistribution \
-XX:+PrintGCDetails \
-XX:+PrintGCTimeStamps \
-Xloggc:/var/log/cassandra/gc.log \
4) number of cores on your system. How busy is the s
I am having some reliability problems in my Cassandra cluster which I am
almost certain is due to GC. I was about to start delving into the guts of
the problem by turning on GC logging but I have never done any serious java
GC tuning before (time to learn I guess). As a first step however, I was
ho
