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From Edward Capriolo <edlinuxg...@gmail.com>
Subject Re: dynamic switch works with NetworkSTrategy NOT SimpleStrategy..solution followsŠ.
Date Mon, 11 Mar 2013 16:16:44 GMT
You should file a JIRA if dsnitch only works with LOCAL_QUORUM something is
very wrong.

On Mon, Mar 11, 2013 at 9:58 AM, Hiller, Dean <Dean.Hiller@nrel.gov> wrote:

> Well, we finally have dynamic switch working.  It seems to switch nodes to
> a Remote node and SimpleSTrategy can not deal with that well.  Also, we had
> to move to CL=QUOROM_LOCAL instead of QUOROM.
>
> So for those of you that want cassandra to keep performing well when one
> node starts to get really slow, make sure you have
>
>  1.  NetworkTopologyStrategy set
>  2.  Have CL=QUOROM_LOCAL
>
> We had to dive into the code to figure all that out.  I hope it helps
> someone else.
>
> Later,
> Dean
>
> From: aaron morton <aaron@thelastpickle.com<mailto:aaron@thelastpickle.com
> >>
> Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Date: Monday, March 11, 2013 6:48 AM
> To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <
> user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
> Subject: Re: has anyone used dynamic snitch at all
>
> Check that read_repair_chance on the CF's is 0.1, not the old 1.0
>
> Wait at least 10 minutes for the DynamicSnitch to re-calculate.
>
> Use the org.apache.cassandra.db:type=DynamicEndpointSnitch MBean to see
> what scores it has given the nodes.
>
> Cheers
>
> -----------------
> Aaron Morton
> Freelance Cassandra Consultant
> New Zealand
>
> @aaronmorton
> http://www.thelastpickle.com
>
> On 8/03/2013, at 11:40 AM, Edward Capriolo <edlinuxguru@gmail.com<mailto:
> edlinuxguru@gmail.com>> wrote:
>
> dynamic_snitch=true is the default. So it is usually on "wrapping" other
> snitches. I have found several scenarios where it does not work exactly as
> your would expect.
>
> On Fri, Mar 8, 2013 at 2:26 PM, Hiller, Dean <Dean.Hiller@nrel.gov<mailto:
> Dean.Hiller@nrel.gov>> wrote:
> Our test setup
>
> 4 nodes, RF=3, reads at CL=QUOROM and we tried CL=TWO
> Tell the network card to slow down every packet on node 2
> After fixing astyanax to not go to node 2 anymore, we are still seeing
> cassandra have issues as it seems to be involving node 2 somehow.  If we
> take node 2 down, it all speeds back up.
>
> We are trying to get this working such that a slow node in cassandra does
> not impact our customers.
>
> We are in 1.2.2 and added the following properties….(our properties show
> PropertyFileSnitch though I see the keyspace has
> org.apache.cassandra.locator.SimpleStrategy set probably because it was
> created through a tool instead of CLI…shucks)….anyways, I still expected
> dynamic snitch to work….
>
> # controls how often to perform the more expensive part of host score
> # calculation
> dynamic_snitch: true
> dynamic_snitch_update_interval_in_ms: 100
> # controls how often to reset all host scores, allowing a bad host to
> # possibly recover
> dynamic_snitch_reset_interval_in_ms: 600000
> # if set greater than zero and read_repair_chance is < 1.0, this will allow
> # 'pinning' of replicas to hosts in order to increase cache capacity.
> # The badness threshold will control how much worse the pinned host has to
> be
> # before the dynamic snitch will prefer other replicas over it.  This is
> # expressed as a double which represents a percentage.  Thus, a value of
> # 0.2 means Cassandra would continue to prefer the static snitch values
> # until the pinned host was 20% worse than the fastest.
> dynamic_snitch_badness_threshold: 0.1
>
> Any help appreciated,
> Thanks,
> Dean
>
>
>

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