cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Ilya Maykov <ivmay...@gmail.com>
Subject Re: Overwhelming a cluster with writes?
Date Tue, 06 Apr 2010 07:13:52 GMT
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
>

Mime
View raw message