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From Benjamin Black...@b3k.us>
Subject Re: Overwhelming a cluster with writes?
Date Tue, 06 Apr 2010 07:16:35 GMT
I am specifically suggesting you NOT use a heap that large with your
8GB machines.  Please test with 4GB first.

On Tue, Apr 6, 2010 at 12:13 AM, Ilya Maykov <ivmaykov@gmail.com> wrote:
> That does sound similar. It's possible that the difference I'm seeing
> between ConsistencyLevel.ZERO and ConsistencyLevel.ALL is simply due
> to the fact that using ALL slows down the writers enough that the GC
> can keep up. I could do a test with multiple clients writing at ALL in
> parallel tomorrow. If there are still no problems writing at ALL even
> with extra load from additional clients, that might point to problems
> in how async writes are handled vs. sync writes.
>
> I will also do some profiling of the server processes with both ZERO
> and ALL writer behaviors and report back.
>
> RE: JVM_OPTS, I will try running with the "more sane" options (but a
> larger heap) as well.
>
> -- Ilya
>
> On Mon, Apr 5, 2010 at 11:59 PM, Rob Coli <rcoli@digg.com> wrote:
>> On 4/5/10 11:48 PM, Ilya Maykov wrote:
>>>
>>> No, the disks on all nodes have about 750GB free space. Also as
>>> mentioned in my follow-up email, writing with ConsistencyLevel.ALL
>>> makes the slowdowns / crashes go away.
>>
>> I am not sure if the above is consistent with the cause of #896, but the
>> other symptoms ("I inserted a bunch of data really fast via Thrift and GC
>> melted my machine!") sound like it..
>>
>> https://issues.apache.org/jira/browse/CASSANDRA-896
>>
>> =Rob
>>
>

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