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From aaron morton <aa...@thelastpickle.com>
Subject Re: Cassandra nodes loaded unequally
Date Thu, 18 Oct 2012 10:35:48 GMT
At times of high load check the CPU % for the java service running C* to confirm C* is the
source of load. 

If the load is generated from C* check the logs (or use OpsCentre / other monitoring) to see
if it correlated to compaction, or Garbage Collection or repair or high throughput. 

Cheers

-----------------
Aaron Morton
Freelance Developer
@aaronmorton
http://www.thelastpickle.com

On 17/10/2012, at 12:22 PM, Ben Kaehne <ben.kaehne@sirca.org.au> wrote:

> Nothing unusual.
> 
> All servers are exactly the same. Nothing unusual in the log files. Is there any level
of logging that I should be turning on?
> 
> Regards,
> 
> On Wed, Oct 17, 2012 at 9:51 AM, Andrey Ilinykh <ailinykh@gmail.com> wrote:
> With your environment (3 nodes, RF=3) it is very difficult to get
> uneven load. Each node receives the same number of read/write
> requests. Probably something is wrong on low level, OS or VM. Do you
> see anything unusual in log files?
> 
> Andrey
> 
> On Tue, Oct 16, 2012 at 3:40 PM, Ben Kaehne <ben.kaehne@sirca.org.au> wrote:
> > Not connecting to the same node every time. Using Hector to ensure an even
> > distribution of connections accross the cluster.
> >
> > Regards,
> >
> > On Sat, Oct 13, 2012 at 4:15 AM, B. Todd Burruss <btoddb@gmail.com> wrote:
> >>
> >> are you connecting to the same node every time?  if so, spread out
> >> your connections across the ring
> >>
> >> On Fri, Oct 12, 2012 at 1:22 AM, Alexey Zotov <azotov@griddynamics.com>
> >> wrote:
> >> > Hi Ben,
> >> >
> >> > I suggest you to compare amount of queries for each node. May be the
> >> > problem
> >> > is on the client side.
> >> > Yoy can do that using JMX:
> >> > "org.apache.cassandra.db:type=ColumnFamilies,keyspace=<YOUR
> >> > KEYSPACE>,columnfamily=<YOUR CF>","ReadCount"
> >> > "org.apache.cassandra.db:type=ColumnFamilies,keyspace=<YOUR
> >> > KEYSPACE>,columnfamily=<YOUR CF>","WriteCount"
> >> >
> >> > Also I suggest to check output of "nodetool compactionstats".
> >> >
> >> > --
> >> > Alexey
> >> >
> >> >
> >
> >
> >
> >
> > --
> > -Ben
> 
> 
> 
> -- 
> -Ben


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