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From li wei <liwei...@yahoo.com>
Subject Re: Quick help on Cassandra please: cluster access and performance
Date Wed, 09 Jun 2010 19:47:25 GMT
Thanks a lot.
We are set READ one, WRITE ANY. Is this better than QUORUM in performance.

Thanks.

Do you think the cassandra  Cluster (with 2 or  nodes) should be always faster than Single
one node in the reality and theory?
Or it depends?

Thanks again!




----- Original Message ----
From: Per Olesen <pol@trifork.com>
To: "user@cassandra.apache.org" <user@cassandra.apache.org>
Sent: Wed, June 9, 2010 3:33:20 PM
Subject: Re: Quick help on Cassandra please: cluster access and performance

> How to set  "write and read with QUORUM"?

You set this through each thrift api call you are making through your java code. See http://wiki.apache.org/cassandra/API

> They are run physically separate hw (But same since they are VM)

So they share disk.

I think this can have an influence. As I understand it, cassandra can be fast on writes because
its storage format is designed so that it needs to do very few random io, which results in
fever seeks. And I think part of the good read performance comes from data on keys being distributed
onto different nodes, which then means distributed reads on separate disks.

When nodes share disk, I think a lot of this is negated.


      

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