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From Tamar Fraenkel <>
Subject Re: READ messages dropped
Date Fri, 12 Oct 2012 07:24:24 GMT
Thanks for the response. My cluster is in a bad state those recent days.

I have 29 CFs, and my disk is 5% full... So I guess the VMs still have more
space to go, and I am not sure this is considered many CFs.

But maybe I have memory issues. I enlarge cassandra memory from about ~2G
to ~4G (out of ~8G). This was done because at that stage I had lots of key
caches. I then reduced them to almost 0 on all CF. I guess now I can reduce
the memory back to ~2 or ~3 G. Will that help?
*Tamar Fraenkel *
Senior Software Engineer, TOK Media

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On Thu, Oct 11, 2012 at 10:46 PM, Tyler Hobbs <> wrote:

> On Wed, Oct 10, 2012 at 3:10 PM, Tamar Fraenkel <>wrote:
>> What I did noticed while looking at the logs (which are also running
>> OpsCenter), is that there is some correlation between the dropped reads and
>> flushes of OpsCenter column families to disk and or compactions. What are
>> the rollups CFs? why is there so much traffic in them?
> The rollups CFs hold the performance metric data that OpsCenter stores
> about your cluster.  Typically these aren't actually very high traffic
> column families, but that depends on how many column families you have
> (more CFs require more metrics to be stored).  If you have a lot of column
> families, you have a couple of options for reducing the amount of metric
> data that's stored:
> Assuming you don't have a large number of CFs, your nodes may legitimately
> be nearing capacity.
> --
> Tyler Hobbs
> DataStax <>

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