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From Lisen Mu <imm...@gmail.com>
Subject Re: Cassandra use cases: as a datagrid ? as a distributed cache ?
Date Thu, 29 Apr 2010 04:19:52 GMT
Facebook did a lot of work to keep their huge memcache
cluster consistent and fault-tolerant.
I think a cache infrastructure like Cassandra would make that a lot easier.

On Thu, Apr 29, 2010 at 11:54 AM, Lisen Mu <immars@gmail.com> wrote:

>
> http://www.reddit.com/r/programming/comments/bcqhi/reddits_now_running_on_cassandra/
>
> It seems to me that they are still using Cassandra in persistant storage
> layer as a replacement of memcachedb, not in cache layer.
>
> I'm new here with Cassandra actually, but now I'm also curious about the
> possibility of using cassandra as cache.
> the main concern is repair-on-read strategy, the secondary is commitlog.
>
> If I'm correct about this, every read request to cassandra will trigger
> several (N-1) message between cassandra nodes.
> In our current traditional memcached + mysql set up, our intranet is kind
> of busy already. I think It would be a burden if message is flooding between
> memcached servers.
>
> In fact, In my opinion, what happend to our db is happening again in cache
> layer:
>
> First, we have nonsql Cassandra, saver of the day.
> But we are not going to let Cassandra carry the weight of page view
> directly, so we still need cache.
> Eventually we have to shard the cache to scale, and replicate to handle hot
> spot.
> In this stage, it would be a HUGE pity if we cannot reuse Cassandra's
> exclusively outstanding ability of handling distribution problem.
>
> So why not provide a kind of Cassandra Daemon, so we can write adapter for
> memcached etc. to construct a pure-in-memory distributed cache layer?
>
> On Tue, Apr 27, 2010 at 9:47 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
>
>> On Mon, Apr 26, 2010 at 9:04 AM, Dominique De Vito
>> <dominique.devito@thalesgroup.com> wrote:
>> > (1) has anyone already used Cassandra as an in-memory data grid ?
>> > If no, does anyone know how far such a database is from, let's say,
>> Oracle
>> > Coherence ?
>> > Does Cassandra provide, for example, a (synchronized) cache on the
>> client
>> > side ?
>>
>> If you mean an in-process cache on the client side, no.
>>
>> > (2) has anyone already used Cassandra as a distributed cache ?
>> > Are there some testimonials somewhere about this use case ?
>>
>> That's basically what reddit is using it for.
>> http://blog.reddit.com/2010/03/she-who-entangles-men.html
>>
>> --
>> Jonathan Ellis
>> Project Chair, Apache Cassandra
>> co-founder of Riptano, the source for professional Cassandra support
>> http://riptano.com
>>
>
>

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