Kevin Closson's Blog: Platforms, Databases and Storage

When it comes to storage protocols, the big storage vendors are sending a clear message: Some is good, more must be better!

NAS, CAS, What a Mess (That Almost Rhymes)
Yes, Oracle cares about Oracle over NFS, and clustered storage is taking off, but the clustered storage offerings are fracturing into structured versus unstructured data optimization and that is a bad choice to have to make.

Back in June 2006, Tony Asaro of the Enterprise Storage Group covered clustered storage in this SearchStorage.com article. He said:

Clustered storage is gaining ground with an increasing number of vendors and systems in today’s market. Over time, clustered storage will be a requisite architectural design element for all storage systems.

The article covers a lot of different clustered storage offerings running the gamut from products like Isilon to CAS technology such as the EMC Centera and mention of PolyServe oddly listed alongside 3Par who partners with PolyServe for scalable NAS. One particular quote in the article stands out:

The Isilon IQ NAS storage system is one of the best examples of a true storage cluster.

Special Purpose Storage
While this may be true, I want to blog about a very important issue that I see arising out of the clustered storage wars. You see, so many of these interesting technologies are very special purpose. Some do streaming media well, others do seismic, others do RDBMS, but few—if not only one—do it all. Deploying special purpose storage technology means you are certain to have more than one kind of storage. For instance, if you adopt EMC Centera for unstructured data, you are going to need some other solution for your structured data—and since this is an Oracle blog we’ll presume Oracle is charged with your structured data.

Centera Storage is Optimized for Databases
“Hold it, Kevin”, you say. I can hear it already. I know, you read this EMC solution brief covering Centera posted on Oracle’s website! It says (emphasis added by me):

[…] Centera’s unique storage capabilities, you can centralize and manage massive volumes of information generated by all aspects of your organization […]

A document on Oracle’s website states Centera handles information generated by all aspects of your organization. Certainly that must also include the things you cram into your ERP database! No, CAS is an EMC term for write-once, or in their terminology “fixed content.” In short they implement WORM on ordinary magnetic media. Centera is not for databases.

So Oracle and EMC both recommend Centera for some of your data. How many different types of storage presentation do you want? What do you do with your database then? Oh, of course, I know, ASM. Centera is a network attached storage device so if you are settling on IP, wouldn’t life be simpler with NAS for the database too? But as I pointed out in this blog entry about ASM over NFS, EMC specifically recommends against combining ASM and NFS. So how many different connectivity models do you want? See, what I don’t get is how the market tolerates having products marketed to them in a way that doesn’t have their best interests in mind. It suits EMC quite well to sell you some Centera and some Celerra for NFS or even a mix of Centera and DMX via FCP (FCP is expensive). Any storage vendor that pushes Content DB will get a head nod from Oracle, but in the end, Content DB runs on all major platforms. So who are the forces behind this drive towards such special purpose and fractured storage management architectures?

Unlike Isilon and EMC file serving, with PolyServe you can buy any commodity hardware. And unlike Isilon and EMC, you can choose Windows Server or Linux—no proprietary embedded operating system. And most importantly—unlike Isilon and EMC—with PolyServe you get general purpose network attached clustered storage. So, sure, do your Content DB and Oracle Database (RAC included) all in one management infrastructure. Makes sense to me, but of course I’m biased.

Isilon: The Best Example of a True Storage Cluster
Yes, Isilon is a true clustered storage, but the product doesn’t support the Oracle database. Yet another special purpose offering. But, as I said here, I wish Isilon well. We are, after all, kindred spirits in this clustered storage wave. 

OK, there, I shamelessly plugged the outfit I work for <smiley face>.