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From Jack Krupansky <jack.krupan...@gmail.com>
Subject Re: Production with Single Node
Date Fri, 22 Jan 2016 22:53:58 GMT
You do of course have the simple technical matters, most of which need to
be addressed with a proof of concept implementation, related to memory,
storage, latency, and throughput. I mean, with a scaled cluster you can
always add nodes to increase capacity and throughput, and reduce latency,
but with a single node you have limited flexibility.

Just to be clear, Cassandra is still not recommended for "fat nodes" - even
if you can fit tons of data on the node, you may not have the computes to
satisfy throughput and latency requirements. And if you don't have enough
system memory the amount of storage is irrelevant.

Back to my original question:
How much data (rows, columns), what kind of load pattern (heavy write,
heavy update, heavy query), and what types of queries (primary key-only,
slices, filtering, secondary indexes, etc.)?

I do recall a customer who ran into problems because they had SSD but only
a very limited amount so they were running out of storage. Having enough
system memory for file system caching and offheap data is important as well.


-- Jack Krupansky

On Fri, Jan 22, 2016 at 5:07 PM, John Lammers <john.lammers@karoshealth.com>
wrote:

> Thanks for your response Jack.
>
> We are already sold on distributed databases, HA and scaling.  We just
> have some small deployments coming up where there's no money for servers to
> run multiple Cassandra nodes.
>
> So, aside from the lack of HA, I'm asking if a single Cassandra node would
> be viable in a production environment.  (There would be RAID 5 and the RAID
> controller cache is backed by flash memory).
>
> I'm asking because I'm concerned about using Cassandra in a way that it's
> not designed for.  That to me is the unsettling aspect.
>
> If this is a bad idea, give me the ammo I need to shoot it down.  I need
> specific technical reasons.
>
> Thanks!
>
> --John
>
> On Fri, Jan 22, 2016 at 4:47 PM, Jack Krupansky <jack.krupansky@gmail.com>
> wrote:
>
>> Is single-node Cassandra has the performance (and capacity) you need and
>> the NoSQL data model and API are sufficient for your app, and your dev and
>> ops and support teams are already familiar with and committed to Cassandra,
>> and you don't need HA or scaling, then it sounds like you are set.
>>
>> You asked about risks, and normally lack of HA and scaling are
>> unacceptable risks when people are looking at distributed databases.
>>
>> Most people on this list are dedicated to and passionate about
>> distributed databases, HA, and scaling, so it is distinctly unsettling when
>> somebody comes along who isn't interested in and committed to those same
>> three qualities. But if single-node happens to work for you, then that's
>> great.
>>
>> -- Jack Krupansky
>>
>
>

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