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From Thomas van Neerijnen <>
Subject Re: Single Node Cassandra Installation
Date Fri, 16 Mar 2012 12:50:32 GMT
You'll need to either read or write at at least quorum to get consistent
data from the cluster so you may as well do both.
Now that you mention it, I was wrong about downtime, with a two node
cluster reads or writes at quorum will mean both nodes need to be online.
Perhaps you could have an emergency switch in your application which flips
to consistency of 1 if one of your Cassandra servers goes down? Just make
sure it's set back to quorum when the second one returns or again you could
end up with inconsistent data.

On Fri, Mar 16, 2012 at 2:04 AM, Drew Kutcharian <> wrote:

> Thanks for the comments, I guess I will end up doing a 2 node cluster with
> replica count 2 and read consistency 1.
> -- Drew
> On Mar 15, 2012, at 4:20 PM, Thomas van Neerijnen wrote:
> So long as data loss and downtime are acceptable risks a one node cluster
> is fine.
> Personally this is usually only acceptable on my workstation, even my dev
> environment is redundant, because servers fail, usually when you least want
> them to, like for example when you've decided to save costs by waiting
> before implementing redundancy. Could a failure end up costing you more
> than you've saved? I'd rather get cheaper servers (maybe even used off
> ebay??) so I could have at least two of them.
> If you do go with a one node solution, altho I haven't tried it myself
> Priam looks like a good place to start for backups, otherwise roll your own
> with incremental snapshotting turned on and a watch on the snapshot
> directory. Storage on something like S3 or Cloud Files is very cheap so
> there's no good excuse for no backups.
> On Thu, Mar 15, 2012 at 7:12 PM, R. Verlangen <> wrote:
>> Hi Drew,
>> One other disadvantage is the lack of "consistency level" and
>> "replication". Both ware part of the high availability / redundancy. So you
>> would really need to backup your single-node-"cluster" to some other
>> external location.
>> Good luck!
>> 2012/3/15 Drew Kutcharian <>
>>> Hi,
>>> We are working on a project that initially is going to have very little
>>> data, but we would like to use Cassandra to ease the future scalability.
>>> Due to budget constraints, we were thinking to run a single node Cassandra
>>> for now and then add more nodes as required.
>>> I was wondering if it is recommended to run a single node cassandra in
>>> production? Are there any other issues besides lack of high availability?
>>> Thanks,
>>> Drew

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