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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: Viability of running on EC2
Date Sat, 13 Jun 2009 16:33:21 GMT
IMO the biggest downside to running on EC2 is that IO is terrible.  I
haven't done benchmarks, but anecdotally disk performance in
particular seems like an order of magnitude slower than you'd get on
non-virtual disks.  So that is worth investigating before assuming
that the price/performance on EC2 is what you think it is.

Other than that, Cassandra is designed to emphasize availability so it
should work fine in the situations you describe.  Hinted handoff in
particular will get writes to the right nodes quickly when machines
come back online.  (However, Cassandra is not yet good at dealing with
machines becoming permanently dead.)

Of course if _all_ of some keys' replicas are temporarily partitioned
off from you you won't be able to read that data until they are
visible again.

-Jonathan

On Sat, Jun 13, 2009 at 11:20 AM, Anthony
Molinaro<anthonym@alumni.caltech.edu> wrote:
> Hi,
>
>  I was wondering what the viability of running cassandra on ec2 was.
> I believe that it currently runs on some pretty hefty hardware at
> facebook, so I'm wondering what the minimum hardware config is
> (in other words can I run it on a cluster of 2core 4GB machines)?
> Also, running on Amazon means no multicast, network partitions and
> machines just disappearing.  How does cassandra deal with these
> constraints/failures?
>
> Thanks for information,
>
> -Anthony
>
> --
> ------------------------------------------------------------------------
> Anthony Molinaro                           <anthonym@alumni.caltech.edu>
>

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