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From "Hiller, Dean" <Dean.Hil...@nrel.gov>
Subject Re: LCS and counters
Date Tue, 05 Mar 2013 16:54:33 GMT
+1.  We are trying to figure that all out too.

I don't know if it helps but we finally upgraded to 1.2.2 which is supposed to have better
LCS support from what I understand.  We did lots of QA testing and jumped from 1.1.4.  Rolling
restart did not work at all in QA so we went with take the whole cluster down instead and
used these steps after having a cassandra-1.2.2 deployed and updating all property files correctly
as well.  (snapshot had to be done before drain oddly enough :( :( since drain seemed to shut
down some ports that nodetool couldn't work).

#on the node itself
clush -g datanodes -l cassandra nodetool -h localhost -p 7199 snapshot databus5 -t 1.2.2a
#drain shuts down ports so you can't do a snapshot....
clush -g datanodes -l cassandra nodetool drain
#AS ROOT...
./cassandraStop.sh
clush -g datanodes rm /opt/cassandra
clush -g datanodes ln -s /opt/cassandra-1.2.2 /opt/cassandra
#BACK to cassandra(it won't run as root anyways as not in path)
cassandraStart.sh



From: Alain RODRIGUEZ <arodrime@gmail.com<mailto:arodrime@gmail.com>>
Reply-To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Date: Tuesday, March 5, 2013 9:50 AM
To: "user@cassandra.apache.org<mailto:user@cassandra.apache.org>" <user@cassandra.apache.org<mailto:user@cassandra.apache.org>>
Subject: Re: LCS and counters

Well no one says my assertion is false, so it is probably true.

Going further, what would be the steps to migrate from STC to LCS ? Is there any precautions
to take doing it using C*1.1.6 (like removing commit logs since drain is broken) ?

Any insight or link on this procedure would be appreciated.


2013/2/25 Janne Jalkanen <Janne.Jalkanen@ecyrd.com<mailto:Janne.Jalkanen@ecyrd.com>>

At least for our use case (reading slices from varyingly sized rows from 10-100k composite
columns with counters and hundreds of writes/second) LCS has a nice ~75% lower read latency
than Size Tiered. And compactions don't stop the world anymore.  Repairs do easily trigger
a few hundred compactions though, but it's not that bad.

/Janne

On Feb 25, 2013, at 17:10 , Alain RODRIGUEZ <arodrime@gmail.com<mailto:arodrime@gmail.com>>
wrote:

> Hi
>
> I am just wondering... Wouldn't it always be worth it to use LCS on counter CF since
LCS is optimized for reads and that writing a counter always require a read ?
>
> Alain



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