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From William Oberman <ober...@civicscience.com>
Subject Re: Ec2Snitch + NetworkTopologyStrategy if only in one region?
Date Wed, 20 Apr 2011 15:15:17 GMT
Also for the new users like me, don't assume DC1 is a keyword like I did.  A
working example of a keyspace in EC2 is:

create keyspace test with replication_factor=3 and strategy_options =
[{us-east:3}] and
placement_strategy='org.apache.cassandra.locator.NetworkTopologyStrategy';

For a single DC in EC2 deployment.  I felt silly afterwards, but I couldn't
find official docs on the structure of strategy_options anywhere.

will

On Wed, Apr 13, 2011 at 5:14 PM, William Oberman
<oberman@civicscience.com>wrote:

> One last coda, for other noobs to cassandra like me.  If you use
> NetworkTopologyStrategy with replication_factor > 1, make sure you have EC2
> instance in multiple availability zones.  I was doing baby steps, and tried
> doing a cluster in one AZ (before spreading to multiple AZs) and was getting
> the most baffling errors ("cassandra_UnavailableException").  I finally
> thought to check the cassandra server logs (after debugging the client code,
> firewalls, etc... painstakingly for connectivity problems), and it ends up
> my cassandra cluster was considering itself "unavailable" as it couldn't
> replicate as much as it wanted to.  I kind of wish a different word than
> "unavailable" was chosen for this error condition :-)
>
> will
>
>
> On Tue, Apr 12, 2011 at 10:37 PM, aaron morton <aaron@thelastpickle.com>wrote:
>
>> If you can use standard + encoded I would go with that.
>>
>> Aaron
>>
>> On 13 Apr 2011, at 07:07, William Oberman wrote:
>>
>> Excellent to know! (and yes, I figure I'll expand someday, so I'm glad I
>> found this out before digging a hole).
>>
>> The other issue I've been pondering is a normal column family of encoded
>> objects (in my case JSON) vs. a super column.  Based on my use case, things
>> I've read, etc...  right now I'm coming down on normal + encoded.
>>
>> will
>>
>> On Tue, Apr 12, 2011 at 2:57 PM, Jonathan Ellis <jbellis@gmail.com>wrote:
>>
>>> NTS is overkill in the sense that it doesn't really benefit you in a
>>> single DC, but if you think you may expand to another DC in the future
>>> it's much simpler if you were already using NTS, than first migrating
>>> to NTS (changing strategy is painful).
>>>
>>> I can't think of any downsides to using NTS in a single-DC
>>> environment, so that's the "safe" option.
>>>
>>> On Tue, Apr 12, 2011 at 1:15 PM, William Oberman
>>> <oberman@civicscience.com> wrote:
>>> > Hi,
>>> >
>>> > I'm getting closer to commiting to cassandra, and now I'm in system/IT
>>> > issues and questions.  I'm in the amazon EC2 cloud.  I previously used
>>> this
>>> > forum to discover the best practice for disk layouts (large instance +
>>> the
>>> > two ephemeral disks in RAID0 for data + root volume for everything
>>> else).
>>> > Now I'm hoping to confirm bits and pieces of things I've read about for
>>> > snitch/replication strategies.  I was thinking of using
>>> > endpoint_snitch: org.apache.cassandra.locator.Ec2Snitch
>>> >
>>> placement_strategy='org.apache.cassandra.locator.NetworkTopologyStrategy'
>>> > (for people hitting this from the mailing list or google, I feel
>>> obligated
>>> > to note that the former setting is in cassandra.yaml, and the latter is
>>> an
>>> > option on a keyspace).
>>> >
>>> > But, I'm only in one region. Is using the amazon snitch/networktopology
>>> > overkill given everything I have is in one DC (I believe region==DC and
>>> > availability_zone==rack).  I'm using multiple availability zones for
>>> some
>>> > level of redundancy, I'm just not yet to the point I'm using multiple
>>> > regions.  If someday I move to using multiple regions, would that
>>> change the
>>> > answer?
>>> >
>>> > Thanks!
>>> >
>>> > --
>>> > Will Oberman
>>> > Civic Science, Inc.
>>> > 3030 Penn Avenue., First Floor
>>> > Pittsburgh, PA 15201
>>> > (M) 412-480-7835
>>> > (E) oberman@civicscience.com
>>> >
>>>
>>>
>>>
>>> --
>>> Jonathan Ellis
>>> Project Chair, Apache Cassandra
>>> co-founder of DataStax, the source for professional Cassandra support
>>> http://www.datastax.com
>>>
>>
>>
>>
>> --
>> Will Oberman
>> Civic Science, Inc.
>> 3030 Penn Avenue., First Floor
>> Pittsburgh, PA 15201
>> (M) 412-480-7835
>> (E) oberman@civicscience.com
>>
>>
>>
>
>
> --
> Will Oberman
> Civic Science, Inc.
> 3030 Penn Avenue., First Floor
> Pittsburgh, PA 15201
> (M) 412-480-7835
> (E) oberman@civicscience.com
>



-- 
Will Oberman
Civic Science, Inc.
3030 Penn Avenue., First Floor
Pittsburgh, PA 15201
(M) 412-480-7835
(E) oberman@civicscience.com

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