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From Vladimir Yudovin <vla...@winguzone.com>
Subject Re: High Usage of Survivor Space
Date Thu, 27 Oct 2016 06:52:54 GMT
Hi,



did this high memory usage caused the problems? OOM crashes, GC pauses?



Best regards, Vladimir Yudovin, 

Winguzone - Hosted Cloud Cassandra
Launch your cluster in minutes.





---- On Wed, 26 Oct 2016 21:51:26 -0400Daniel Kleviansky &lt;daniel@kleviansky.com&gt;
wrote ----




Before anyone wastes any time replying, I found out that most of these were not being used,
and manage to drop certain keyspaces and reduce the count of column families to 158.

Thought still a fair number, this seems to have relieved the issue significantly!



Hope this helps someone out at some point, otherwise, sorry for the unnecessary emails. ;)



Daniel




On Thu, Oct 27, 2016 at 11:25 AM, Daniel Kleviansky &lt;daniel@kleviansky.com&gt;
wrote:










-- 

Daniel Kleviansky

System Engineer &amp; CX Consultant

M: +61 (0) 499 103 043 | E: daniel@kleviansky.com | W: http://danielkleviansky.com







​Hi everyone,



Organisation is running Cassandra for Windows v2.2.5

One of our development (non-load testing) clusters has a total of 6 nodes across two DCs,
with an RF = 3:3.

Each node has a total of 16GB of memory, and no JVM options have been modified.




We're seeing what I believe to be unusually high usage of survivor space across all nodes
in the cluster. Some sit at a consistently 100% maxed out state, while others are found at
about 90%.



Initial thoughts is this is linked to high number of keyspaces/column families running on
this particular cluster. There is a total of 28 keyspaces and 412 column families. I have
no empirical evidence to support this theory, hence me reaching out to the mailing list.



Is there any way to verify this theory, and/or discover potential root causes?



Please let me know what other information I can provide, and I'll be sure to get it ASAP.




Kindest regards,

Daniel Kleviansky







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