RE: RAC in NAS

It's kind of inverted actually - NAS can be more expensive than SAN, and SAN can be much worse than NAS. The storage market has expanded in so many different directions that its very difficult to figure out what is the best for your organization. I would generically throw it out like this - assuming apples-to-apples comparison:  

• NAS offers a number of usability enhancements over SAN in RAC environments, notably the fact that NFS is just baked into Linux and removes the need for a CFS
• SAN is generally faster, IO for IO, than NAS. This is because the fibre channel HBAs offload pretty much all of the protocol heavy lifting from the OS, while NAS uses standard ethernet cards, and because SAN arrays tend to have more dedicated chips handling the processing, while the standard NAS (Netapp, Celerra) uses a commoditized processor - a notable exception to this is BlueArc, which has a very cool pipelined dedicated processor technology (you also pay for that, though)
• NAS is generally more manageable than a SAN infrastructure - Ethernet+ TCP/IP+ NFS is a well-documented, well-understood, and well-architected protocol. Fibre Channel is complicated, niche, expensive, and very few people know how it works and how to manage it correctly.
• From a speeds-and-feeds perspective, Fibre Channel is faster than GigE, until 10gigE becomes more standardized. However, I have only seen a few instances where the bandwidth of the pipe becomes a factor in overall performance, especially in database workloads

So - in the end, its what you need and what your organization wants to buy. I'm a big NAS believer, but I've recommended SAN solutions to our customers where I believe it makes sense. I do think there's a lot of exciting things going on in the storage space right now, and I suspect infrastructure will look a lot different five years from now.  

Thanks,
Matt

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of ryan_gaffuri_at_comcast.net
Sent: Wednesday, July 26, 2006 10:41 AM
To: Yavor_Ivanov_at_stemo.bg; dbvision_at_iinet.net.au Cc: Yavor Ivanov; oracle-l_at_freelists.org Subject: Re: RAC in NAS

I am not much of a hardware person..., but I thought NAS was cheaper than SAN and SAN was better? Has that changed or is that an over simplified view?  

Any bench marks comparing the two?  

• Original message -------------- From: "Yavor Ivanov" <Yavor_Ivanov_at_stemo.bg>

> They are planning on 10g Release 2 (10.2.0.2).
> In fact, the IBM guys advised them to take SAN for RAC, not
NAS, but the

> custumer insisted on "the latest, the best, the most
expensive, cutting edge

> technology". The same is for the Oracle release - they take EE
and never ask if

> Standard Edition is fine for them.
>
> Regards,
> Yavor
>
> On Wed, 26 Jul 2006 15:25:07 +0300, Nuno Souto wrote:
>
> > Yavor Ivanov wrote,on my timestamp of 26/07/2006 10:09 PM:
> >>
> >> I had a call from a custumer, who bought 2 IBM servers with
x64 (4

> Xeon64 CPUs per node)
> > > architectures and NAS, seeking for RAC solution on
Windows.

> ; > > Unfortunately, they did not ask anyone before bying the
hardware and now

> they
> > have this so
> > > expensive hardware which is not supported for RAC on
Windows.

> > > Oracle RAC supports only SAN on Windows. So sad.
> >
> > No, not sad. It's what Oracle supports. At most, it's
terminally stupid for

> > the customer to go out and buy hardware without checking
first. But

> > then again, IBM would never ask them to check firstt,
selling comes before

> > all that?...
> >
> >
> >> So I was wondering, if anyone of you tried running RAC on
Linux with

> NAS?
> > > Is it running, and is it supported? Unfortunltely I could
not find

> > > hard statement is it working solution (and for Windows it
is

> > > written that it does NOT work:
> > > http://www.oracle.com/technology/products/database/clus
tering /

> > > certify/tech_generic_window.html ).
> >
> > Haven't yet tried RAC on Linux with anything. Having enough
trouble

> > here making vanilla 9ir2 work fine with ASSM and LOBs in
Linux

> > dedicated. Let alone RAC! But that's another story: for
those

> > with access to Metaclick, seek out the list of bug fixes
planned

> > for 9.2.0.8, then read on the ASSM and LOB bug references
there.

> > Yes, Virginia: we've just hit every single one of them!
> > Fun and games...
> >
> > I don't think NAS is supported for RAC on Linux. However,
I'll stand

> > corrected if anyone knows different. As well, it might help
if you give

> > us a hint on which versions of Oracle and Linux the customer
is

> > planning to run? Or is that pre-determined already by
> > "oh-so-knowledgeable" IBM?
> >
>
> --
> http://www. freeli sts.org/webpage/oracle-l
>
>

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