Question about cassandra (replication)

[Harold Lim <ro...@yahoo.com>]

Hi All,

I posted a similar message on the google groups page. Hopefully, I'll get more feedback here.


I just started reading about dynamo and Cassandra and I am thinking
about possibly using cassandra for my system.

I was reading the dynamo paper and they mentioned about a preference
list for a particular key. Is this preference list configurable?

How does Cassandra choose which nodes are in the preference list?
Also, are the number of replica for each key/column configurable? For
example, can I set the replication factor per key/value?

I read that Cassandra has optimistic replication. What exactly does
that mean? Underneath the hood, how does cassandra maintain/detect the
number of replicas? Does it aggressively replicates an item, when it
detects that the number of replica of a particular item goes below the
specified repliation factor?

Is the replication strategy (when to replicate, aggresiveness, etc)
configurable too?






Thanks,
Harold 


      

Re: Question about cassandra (replication)

[Jonathan Ellis <jb...@gmail.com>]

Rather than post the same question verbatim, it would be more useful
if you explained what you still don't understand after Alexander and
Sandeep's explanations on the google group.

(http://groups.google.com/group/cassandra-user/browse_thread/thread/4330e415e959e9d9)

On Thu, Jun 25, 2009 at 9:11 AM, Harold Lim<ro...@yahoo.com> wrote:
>
> Hi All,
>
> I posted a similar message on the google groups page. Hopefully, I'll get more feedback here.
>
>
> I just started reading about dynamo and Cassandra and I am thinking
> about possibly using cassandra for my system.
>
> I was reading the dynamo paper and they mentioned about a preference
> list for a particular key. Is this preference list configurable?
>
> How does Cassandra choose which nodes are in the preference list?
> Also, are the number of replica for each key/column configurable? For
> example, can I set the replication factor per key/value?
>
> I read that Cassandra has optimistic replication. What exactly does
> that mean? Underneath the hood, how does cassandra maintain/detect the
> number of replicas? Does it aggressively replicates an item, when it
> detects that the number of replica of a particular item goes below the
> specified repliation factor?
>
> Is the replication strategy (when to replicate, aggresiveness, etc)
> configurable too?
>
>
>
>
>
>
> Thanks,
> Harold
>
>
>
>