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From Dan Kinder <dkin...@turnitin.com>
Subject Re: Production with Single Node
Date Fri, 22 Jan 2016 20:54:57 GMT
I could see this being desirable if you are deploying the exact same
application as you deploy in other places with many nodes, and you know the
load will be low. It may be a rare situation but in such a case you save
big effort by not having to change your application logic.

Not that I necessarily recommend it but to answer John's question: my
understanding is that you want to keep it snappy and low-latency you should
watch out for GC pause and consider your GC tuning carefully, it being a
single node will cause the whole show to stop. Presumably your load won't
be very high.

Also if you are concerned with durability you may want to consider changing
commitlog_sync
<https://docs.datastax.com/en/cassandra/1.2/cassandra/configuration/configCassandra_yaml_r.html?scroll=reference_ds_qfg_n1r_1k__commitlog_sync>
to
batch. I believe this is the only way to guarantee write durability with
one node. Again with the performance caveat; under high load it could cause
problems.

On Fri, Jan 22, 2016 at 12:34 PM, Jonathan Haddad <jon@jonhaddad.com> wrote:

> My opinion:
> http://rustyrazorblade.com/2013/09/cassandra-faq-can-i-start-with-a-single-node/
>
> TL;DR: the only reason to run 1 node in prod is if you're super broke but
> know you'll need to scale up almost immediately after going to prod (maybe
> after getting some funding).
>
> If you're planning on doing it as a more permanent solution, you've chosen
> the wrong database.
>
> On Fri, Jan 22, 2016 at 12:30 PM Jack Krupansky <jack.krupansky@gmail.com>
> wrote:
>
>> The risks would be about the same as with a single-node Postgres or MySQL
>> database, except that you wouldn't have the benefit of full SQL.
>>
>> 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.)?
>>
>> -- Jack Krupansky
>>
>> On Fri, Jan 22, 2016 at 3:24 PM, John Lammers <
>> john.lammers@karoshealth.com> wrote:
>>
>>> After deploying a number of production systems with up to 10 Cassandra
>>> nodes each, we are looking at deploying a small, all-in-one-server system
>>> with only a single, local node (Cassandra 2.1.11).
>>>
>>> What are the risks of such a configuration?
>>>
>>> The virtual disk would be running RAID 5 and the disk controller would
>>> have a flash backed write-behind cache.
>>>
>>> What's the best way to configure Cassandra and/or respecify the hardware
>>> for an all-in-one-box solution?
>>>
>>> Thanks-in-advance!
>>>
>>> --John
>>>
>>>
>>


-- 
Dan Kinder
Principal Software Engineer
Turnitin – www.turnitin.com
dkinder@turnitin.com

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