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From Jonathan Ellis <>
Subject Re: Nodes frozen in GC
Date Mon, 07 Mar 2011 21:35:09 GMT
It sounds like you're complaining that the JVM sometimes does stop-the-world GC.

You can mitigate this but not (for most workloads) eliminate it with
GC option tuning.  That's simply the state of the art for Java garbage
collection right now.

On Sun, Mar 6, 2011 at 2:18 AM, ruslan usifov <> wrote:
> 2011/3/6 aaron morton <>
>> Your node is under memory pressure, after the GC there is still 5.7GB in
>> use. In fact it looks like memory usage went up during the GC process.
>> Can you reduce the memtable size, caches or the number of CF's or increase
>> the JVM size? Also is this happening under heavy load ?
> Yes I do bulk load to cluster
> I reduce memtable to 64MB sutuation became better, but it is all the same
> very rare GC more than 15 Sec happens. Can reduce
> flush_largest_memtables_at helps? O may be some GC options?

Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support

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