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Subject: Re: Cassandra with SAN
From: David Schairer <dschairer@humbaba.net>
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Date: Thu, 21 Feb 2013 15:52:13 -0800
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References: 
 <57C7C3CBDCB04F45A57AEC4CB21C0CCD1DB3537C@mbx024-e1-nj-6.exch024.domain.local>
 <CD4BE76C.122C3%mkjellman@barracuda.com>
 <57C7C3CBDCB04F45A57AEC4CB21C0CCD1DB353A3@mbx024-e1-nj-6.exch024.domain.local>
To: user@cassandra.apache.org

"Who breaks a butterfly upon a wheel?"

It will work, but you'd have a distributed database running on a single =
point of failure storage fabric, thus destroying much of your benefits, =
unless you have enough discrete SAN units that you treat them as racks =
in your cassandra topology to ensure that you have data replicated =
across redundant SAN shelves|controllers|etc.

You also would end up with redundancy at cross purposes in that the SAN =
will be striping data that Cassandra is already distributing =
efficiently.

If the SAN is free and unused, it'll be fine as a Cassandra test =
platform.  But I wouldn't spend a penny on SAN hardware instead of a =
much larger distributed cluster with commodity hardware.  Derive your =
redundancy and performance from lots of hardware in lots of places, not =
expensive hardware in one place. =20

--DRS

On Feb 21, 2013, at 3:42 PM, Kanwar Sangha <kanwar@mavenir.com> wrote:

> Ok. What would be the drawbacks J
> =20
> From: Michael Kjellman [mailto:mkjellman@barracuda.com]=20
> Sent: 21 February 2013 17:12
> To: user@cassandra.apache.org
> Subject: Re: Cassandra with SAN
> =20
> No, this is a really really bad idea and C* was not designed for this, =
in fact, it was designed so you don't need to have a large expensive =
SAN.
> =20
> Don't be tempted by the shiny expensive SAN. :)
> =20
> If money is no object instead throw SSD's in your nodes and run 10G =
between racks
> =20
> From: Kanwar Sangha <kanwar@mavenir.com>
> Reply-To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Date: Thursday, February 21, 2013 2:56 PM
> To: "user@cassandra.apache.org" <user@cassandra.apache.org>
> Subject: Cassandra with SAN
> =20
> Hi =96 Is it a good idea to use Cassandra with SAN ?  Say a SAN which =
provides me 8 Petabytes of storage. Would I not be I/O bound =
irrespective of the no of Cassandra machines and scaling by adding
> machines won=92t help ?
> =20
> Thanks
> Kanwar
> =20
> ----------------------------------=20
> Copy, by Barracuda, helps you store, protect, and share all your =
amazing things. Start today: www.copy.com.
>   =AD=AD =20