Sorry to jump on this late. GC is one of my favorite topics. A while ago I
wrote a blob post about C* GC tuning and documented several issues that I
had experienced. It seems it has helped some people in that past, so I am
sharing it here:
http://aryanet.com/blog/cassandra-garbage-collector-tuning
Number of cores: 2x6Cores x 2(HT).
I do agree with you that the the hardware is certainly overestimated for
just one Cassandra, but we got a very good price since we ordered
several 10s of the same nodes for a different project. That's why we use
for multiple cassandra instances.
Jirka H.
On 02/
> each node has 256G of memory, 24x1T drives, 2x Xeon CPU
I don't have first hand experience running Cassandra on such massive
hardware, but it strikes me that these machines are dramatically oversized
to be good candidates for Cassandra (though I wonder how many cores are in
those CPUs; I'm guess
Hi Chris,
On 02/09/2015 04:22 PM, Chris Lohfink wrote:
> - number of tombstones - how can I reliably find it out?
> https://github.com/spotify/cassandra-opstools
> https://github.com/cloudian/support-tools
thanks.
>
> If not getting much compression it may be worth trying to disable it,
> it may
- number of tombstones - how can I reliably find it out?
https://github.com/spotify/cassandra-opstools
https://github.com/cloudian/support-tools
If not getting much compression it may be worth trying to disable it, it
may contribute but its very unlikely that its the cause of the gc pressure
itse
Hi all,
thank you all for the info.
To answer the questions:
- we have 2 DCs with 5 nodes in each, each node has 256G of memory,
24x1T drives, 2x Xeon CPU - there are multiple cassandra instances
running for different project. The node itself is powerful enough.
- there 2 keyspaces, one with 3
: Mark Reddy
To: user@cassandra.apache.org
Cc: cassandra-u...@apache.org; FF Systems
Sent: Sunday, February 8, 2015 1:32 PM
Subject: Re: High GC activity on node with 4TB on data
Hey Jiri,
While I don't have any experience running 4TB nodes (yet), I would recommend
taking a look
The most data I put on a node with spinning disk is 1TB.
What are the machine specs? Cpu, memory, etc and what is the read/write
pattern-heavy ingest rate/heavy read rate and how ling do you keep data in the
cluster?
--
Colin Clark
+1 612 859 6129
Skype colin.p.clark
> On Feb 8, 2015, at 2:44
Hey Jiri,
While I don't have any experience running 4TB nodes (yet), I would
recommend taking a look at a presentation by Arron Morton on large nodes:
http://planetcassandra.org/blog/cassandra-community-webinar-videoslides-large-nodes-with-cassandra-by-aaron-morton/
to see if you can glean anythin
Do you have a lot of individual tables? Or lots of small compactions?
I think the general consensus is that (at least for Cassandra), 8GB heaps
are ideal.
If you have lots of small tables it’s a known anti-pattern (I believe)
because the Cassandra internals could do a better job on handling the
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