Kevin Closson's Blog: Platforms, Databases and Storage

BLOG UPDATE 2011.08.11 : For years my criticism of Oracle Clusterware fencing methodology brought ire from many who were convinced I was merely a renegade. The ranks of “the many” in this case were generally well-intended but overly convinced that Oracle was the only proven clustering technology in existence.  It took many years for Oracle to do so, but they did finally offer support for IPMI fencing integration in the 11.2 release of Oracle Database. It also took me a long time to get around to updating this post.  Whether by graces of capitulation or a reinvention of the wheel, you too can now, finally, enjoy a proper fencing infrastructure. For more information please see: http://download.oracle.com/docs/cd/E11882_01/rac.112/e16794/admin.htm#CHDGIAAD

PolyServe to Open Source Products in Wake of “New” Oracle Unbreakable Linux

You all know I currently work for PolyServe. Over the last 5 years I cannot count how many times it has been recommended to us that we open source PolyServe Database Utility for Oracle.Back when Dave Dargo’s office was pushing the Unbreakable Linux program (circa 2002), the ecosystem for Oracle on Linux started to get dicey really fast. You see, when Unbreakable Linux started, it was a program that:

• Mandated that all software on your system—except Oracle of course—be open source
• You still have a support contract with Redhat or SuSE

Meeting these criteria allowed you to call Oracle Support with purely Operating System issues. I’m still waiting for anyone to comment on just how helpful that program was for you. It seemed like very dubious value add to me.

What about Open Source Cluster File Systems?

Over the years, we’ve been asked why our customers pay for our product when OCFS is free and GFS is available. Historically, it was because it worked and the others were seen as emerging technology. I question that supposition because GFS just about died in the hands of Sistina and OCFS has always been too rudimentary for general purpose use. I know OCFS2 is reportedly a general purpose filesystem, if that is true for you in production, that’s good. If you have only heard that rumor, I recommend my philosophy that belief should only be borne of testing.

SuSE was the only distro to adopt OCFS2 since Redhat was working on GFS. It may seem like trivial pursuit, but Novell Corporate IT actually run Oracle on PolyServe—but I digress.

Dark Dirty Secrets About Free Stuff

Oracle has been stating that OCFS is “good enough” for years, and after OCFS2 was touted as “general purpose”, SuSE decided to be nice and include it in their distribution—but they never told anyone that it doesn’t work. The voice of authority on what OCFS2 can do is actually SuSE, and Lars Marowsky-Brée is the voice of voices there since he works in the group that is trying to make free clustering solutions work. In this suse-oracle email list installment he writes:

So two nodes is not really sufficient with OCFS2 to protect against node failures – you need three at least for the majority quorum to be meaningful.

That was on 11 April 2006. I bet you haven’t heard that two node clusters with OCFS2 are split-brain poster children from anyone but this blog, right? What’s the big deal? If the stuff doesn’t work, why are you being told it does?

Of these two, GFS is at least close to pole position. It has a quality fencing model and actually works—at least their STONITH model that is. I wrote about fencing in this paper, and will go into the topic further here once the dust settles from Oracle OpenWorld. But just because it is functional doesn’t mean it performs. Sistina had all sorts of problems working out the locking model with GFS. Redhat didn’t inherit any favors in that regard. Here is an independent study of Linux CFS alternatives for unstructured data—the real kingpin performance metric for file systems.

What About Oracle Support

Now that is a great generic topic—but not for this post. After Oracle shook things up and muddied the water back on 2002 with Unbreakable Linux 1.0, they changed their stance on database support—when using third party clustering solutions—about 42 times. Eventually, Oracle instituted a program for third party cluster filesystems and clusterware compatibility which is discussed here. The RAC Technology Compatibility Matrix in Oracle Metalink is the final say on such matters.

The Linux ecosystem has been a train wreck not due to technology interoperability so much as the constant heavy-handedness by such companies as Oracle when it comes to partnering. In fact, Redhat has consistently tried to freeze out non-open source partners. Maybe this will change their attitude.

Is it really Redhat support that is slowing Linux adoption in the enterprise as Larry says? I think not.

1-800-Call-Larry—Who Ya Gonna Call? TSANet To the Rescue.

Oh, I know, we all want a single-source provider for all support. Uh huh, nothing like feeling really, truly, alone in the world. Have a complex problem and only a single 1-800 number to call? Good luck. Isn’t that why proprietary solutions were so despised? Isn’t the openness of Open Systems why Oracle is where it is today? What happened?

If this trend toward solutions consolidation continues, we are all going to sorely miss the days when there were multiple providers in a given solution who were fighting for your business and success. That is, after all, why TSANet is so crucial and why you need to know more about it. See, if you have a multi-provider solution where the providers are signatories to TSANet, there is no “finger pointing”. Ahh, yes, the fabled “finger pointing”. Unless you get a single provider—soup to nuts—there are going to be multiple players. In a problem resolution scenario, the only finger pointers are the big players. They are the only ones that can afford to lose your business. Does anyone think that, say, a small infrastructure player in a multi-vendor solution can actually get away with being the finger pointer? Heavens no. It is always the biggest player that tries to dismiss off their problem to the motivated, smaller new comer. Alas, TSANet has always been the protection from such poor business practice.

Deployment Standards

Imagine a datacenter that had both Windows (with SQL Server) and Linux running critical applications. Imagine further the need to consolidate and provide high availability at the same time. Now, quick, pick your solution. How is Unbreakable Linux (redux) or GFS or OCFS supposed to help at all?I’ve had dozens of you readers ask me why PolyServe. The answer is that only PolyServe solves this problem on both Linux and Windows. Our customers want a cluster deployment model that works for both Windows and Linux—imagine that!Doing things the same way regardless of operating system sounds like a good idea to me.

Open Source—The Perfect Business Model

Well, PolyServe missed the chance to open source our products when the timing was right. Had we, there is a chance that the same thing that just happened to Redhat could have happened to us. What a great business model.You get venture capital funding, build a world-class product, build a support ecosystem, open source it, get hundreds of customers in production, then someone like Oracle takes over for you. That almost makes the add-revenue model of the burning-piles-of-cash.com startups of the 1990’s like pretty attractive.

So, no, we won’t be doing the open source thing. After Larry’s announcement, it looks less and less attractive every day.

Solaris 10 on AMD anyone? Hmmm…