Cassandra Version 0.6.1 OpenJDK Server VM (build 14.0-b16, mixed mode) Import speed is about 10MB/s for the full cluster; if a compaction is going on the individual node is I/O limited tpstats: caught me, didn't know this. I will set up a test and try to catch a node during the critical time.
Thanks, Roland 2010/4/26 Chris Goffinet <goffi...@digg.com> > Which version of Cassandra? > Which version of Java JVM are you using? > What do your I/O stats look like when bulk importing? > When you run `nodeprobe -host XXXX tpstats` is any thread pool backing up > during the import? > > -Chris > > > 2010/4/26 Roland Hänel <rol...@haenel.me> > > I have a cluster of 5 machines building a Cassandra datastore, and I load >> bulk data into this using the Java Thrift API. The first ~250GB runs fine, >> then, one of the nodes starts to throw OutOfMemory exceptions. I'm not using >> and row or index caches, and since I only have 5 CF's and some 2,5 GB of RAM >> allocated to the JVM (-Xmx2500M), in theory, that should happen. All inserts >> are done with consistency level ALL. >> >> I hope with this I have avoided all the 'usual dummy errors' that lead to >> OOM's. I have begun to troubleshoot the issue with JMX, however, it's >> difficult to catch the JVM in the right moment because it runs well for >> several hours before this thing happens. >> >> One thing gets to my mind, maybe one of the experts could confirm or >> reject this idea for me: is it possible that when one machine slows down a >> little bit (for example because a big compaction is going on), the memtables >> don't get flushed to disk as fast as they are building up under the >> continuing bulk import? That would result in a downward spiral, the system >> gets slower and slower on disk I/O, but since more and more data arrives >> over Thrift, finally OOM. >> >> I'm using the "periodic" commit log sync, maybe also this could create a >> situation where the commit log writer is too slow to catch up with the data >> intake, resulting in ever growing memory usage? >> >> Maybe these thoughts are just bullshit. Let me now if so... ;-) >> >> >> >
