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From William Oberman <ober...@civicscience.com>
Subject Re: advice for EC2 deployment
Date Wed, 27 Apr 2011 13:29:43 GMT
Thanks Sasha.  Fortunately/unfortunately I did realize the default & current
behavior of the Ec2Snitch, but my application isn't multi-region capable
(yet), so I need to get intra-region redundancy.  And having a
SingleRegionEc2Snitch that did DC=ec2zone and RACK=??? would be much better
for me (for now).

On Wed, Apr 27, 2011 at 9:21 AM, Sasha Dolgy <sdolgy@gmail.com> wrote:

> Hi William,
>
> The default behavior of Ec2Snitch is outlined below:
>
>
> http://svn.apache.org/repos/asf/cassandra/trunk/src/java/org/apache/cassandra/locator/Ec2Snitch.java
>
>        // Split "us-east-1a" or "asia-1a" into "us-east"/"1a" and
> "asia"/"1a".
>        String azone = new String(b ,"UTF-8");
>        String[] splits = azone.split("-");
>        ec2zone = splits[splits.length - 1];
>        ec2region = splits.length < 3 ? splits[0] : splits[0]+"-"+splits[1];
>        logger.info("EC2Snitch using region: " + ec2region + ", zone:
> " + ec2zone + ".");
>
> ApplicationState.DC = ec2region
> ApplicationState.RACK = ec2zone
>
> We leverage cassandra instances in APAC, US & Europe ... so it's
> important for us to know that we have one data center in each 'region'
> and multiple racks per DC ...
>
> -sasha
>
> On Wed, Apr 27, 2011 at 3:06 PM, William Oberman
> <oberman@civicscience.com> wrote:
> > It's great advice, but I'm still torn.  I've never done multi-region work
> > before, and I'd prefer to wait for 0.8 with built-in inter-node security,
> > but I'm otherwise ready to roll (and need to roll) cassandra out sooner
> than
> > that.
> >
> > Given how well my system held up with a total single AZ failure, I'm
> really
> > leaning on starting by treating AZ's as DCs, and racks as... random?  I
> > don't think that part matters.  My question for today is to just use the
> > property file snitch, or to roll my own version of Ec2Snith that does AZ
> as
> > DC.
> >
> > I do increase my risk being single region to start, so I was going to
> figure
> > out how to push snapshots to S3.  One question on that note: is it better
> to
> > try and snapshot all nodes at roughly the same point in time, or is it
> > better to do "rolling snapshots"?
> >
> > will
>



-- 
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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