7-Mode to Clustered ONTAP Transition

I normally deal with different aspects of storage (arguably far more exciting) but I thought I would write something to provide some common sense perspective on the current state of 7-Mode to cDOT adoption.

I will tackle the following topics:

  1. cDOT vs 7-Mode capabilities
  2. Claims that not enough customers are moving to cDOT
  3. 7-Mode to cDOT transition is seen by some as difficult and expensive
  4. Some argue it might make sense to look at competitors and move to those instead
  5. What programs and tools are offered by NetApp to make transition easy and quick
  6. Migrating from competitors to cDOT

cDOT vs 7-Mode capabilities

I don’t want to make this into a dissertation or take a trip down memory lane. Suffice it to say that while cDOT has most of the 7-Mode features, it is internally very different but also much, much more powerful than 7-Mode – cDOT is a far more capable and scalable storage OS in almost every possible way (and the roadmap is utterly insane).

For instance, cDOT is able to nondisruptively do anything, including crazy stuff like moving SMB shares around cluster nodes (moving LUNs around is much easier than dealing with the far more quirky SMB protocol). Some reasons to move stuff around the cluster could be node balancing, node evacuation and replacement… all done on the fly in cDOT, regardless of protocol.

cDOT also handles Flash much better (cDOT 8.3.x+ can be several times faster than 7-Mode for Flash on the exact same hardware). Even things like block I/O (FC and iSCSI) are completely written from the ground up in cDOT. Cloud integration. Automation. How failover is done. Or how CPU cores are used, how difficult edge conditions are handled… I could continue but then the ADD-afflicted would move on, if they haven’t already…

In a nutshell, cDOT is a more flexible, forward-looking architecture that respects the features that made 7-Mode so popular with customers, but goes incredibly further. There is no competitor with the breadth of features available in cDOT, let alone the features coming soon.

cDOT is quite simply the next logical step for a 7-Mode customer.

Not enough customers moving to cDOT?

The reality is actually pretty straightforward.

  • Most new customers simply go with cDOT, naturally. 7-Mode still has a couple of features cDOT doesn’t, and if those features are really critical to a customer, that’s when someone might go with 7-Mode today. With each cDOT release the feature delta list gets smaller and smaller. Plus, as mentioned earlier, cDOT has a plethora of features and huge enhancements that will never make it to 7-Mode, with much more coming soon.
  • The things still missing in cDOT (like WORM) aren’t even offered by the majority of storage vendors… many large customers use our WORM technology.
  • Large existing customers, especially ones running critical applications, naturally take longer to cycle technologies. The average time to switch major technologies (irrespective of vendor) is around 5 years. The big wave of cDOT transitions hasn’t even hit yet!
  • Given that cDOT 8.2 with SnapVault was the appropriate release for many of our customers and 8.3 the release for most of our customers, a huge number of systems are still within that 5-year window prior to converting to cDOT, given when those releases came out.
  • Customers with mission-critical systems will typically not convert an existing system – they will wait for the next major refresh cycle. Paranoia rules in those environments (that’s a general statement regardless of vendor). And we have many such customers.

7-Mode to cDOT transition is seen by some as difficult and expensive

This is a fun one, and a favorite FUD item for competitors and so-called “analysts”. I sometimes think we confused people by calling cDOT “ONTAP”. I bet expectations would be different if we’d called it “SuperDuper ClusterFrame OS”.

You see, cDOT is radically different in its internals versus 7-Mode – however, it’s still officially also called “ONTAP”. As such, customers are conditioned to super-easy upgrades between ONTAP releases (just load the new code and you’re done). cDOT is different enough that we can’t just do that.

I lobbied for the “ClusterFrame” name but was turned down BTW. I still think it rocks.

The fact that you can run either 7-Mode or cDOT on the same physical hardware confuses people even further. It’s a good thing to be able to reuse hardware (software-defined and all that). Some vendors like to make each new rev of the same family line (and its code) utterly incompatible with the last one… we don’t do that.

And for the startup champions: Startups haven’t been around long enough to have seen a truly major hardware and/or software change! (another thing conveniently ignored by many). Nor do they have the sheer amount of features and ancillary software ONTAP does. And of course, some vendors forget to mention what even a normal tech refresh looks like for their fancy new “built from the ground up” box with the extremely exciting name.

We truly know how to do upgrades… probably better than any vendor out there. For instance: What most people don’t know is that WAFL (ONTAP’s underlying block layout abstraction layer) has been quietly upgraded many, many times over the years. On the fly. In major ways. With a backout option. Another vendor’s product (again the one with the extremely exciting name) needed to be wiped twice by as many “upgrades” in one year in order to have its block layout changed.

Here’s the rub:

Transition complexity really depends on how complex your current deployment is, your appetite for change and tolerance of risk. But transition urgency depends on how much you need the fully nondisruptive nature of cDOT and all the other features it has vs 7-Mode.

What I mean by that:

We have some customers that lose upwards of $4m/hour of downtime. The long-term benefits of a truly nondisruptive architecture make any arguments regarding migration efforts effectively moot.

If you are using a lot of the 7-Mode features and companion software (and it has more features than almost any other storage OS), specific tools written only for 7-Mode, older OS clients only supported on 7-Mode, tons of snaps and clones going back to several years’ retention etc…

Then, in order to retain that kind of similar elaborate deployment in cDOT, the migration effort will also naturally be a bit more complex. But still doable. And we can automate most of it. Including moving over all the snapshots and archives!

On the other hand, if you are using the system like an old-fashioned device and aren’t taking advantage of all the cool stuff, then moving to anything is relatively easy. And especially if you’re close to 100% virtualized, migration can be downright trivial (though simply moving VMs around storage systems ignores any snapshot history – the big wrinkle with VM migrations).

Some argue it might make sense to look at competitors and move to those instead

Looking at options is something that makes business sense in general. It would be very disingenuous of me to say it’s foolish to look at options.

But this holds firmly true: If you want to move to a competitor platform, and use a lot of the 7-Mode features, it would arguably be impossible to do cleanly and maintain full functionality (at a bare minimum you’d lose all your snaps and clones – and some customers have several years’ worth of backup data in SnapVault – try asking them to give that up).

This is true for all competitor platforms: Someone using specific features, scripts, tools, snaps, clones etc. on any platform, will find it almost impossible to cleanly migrate to a different platform. I don’t care who makes it. Doesn’t matter. Can you cleanly move from VMware + VMware snaps to Hyper-V and retain the snaps?

Backup/clone retention is really the major challenge here – for other vendors. Do some research and see how frequently customers switch backup platforms… 🙂 We can move snaps etc. from 7-Mode to cDOT just fine 🙂

The less features you use, the easier the migration and acclimatization to new stuff becomes, but the less value you are getting out of any given product.

Call it vendor lock-in if you must, but it’s merely a side effect of using any given device to its full potential.

The reality: it is incredibly easier to move from 7-Mode to cDOT than from 7-Mode to other vendor products. Here’s why…

What programs and tools are offered by NetApp to make transition easy and quick?

Initially, migration of a complex installation was harder. But we’ve been doing this a while now, and can do the following to make things much easier:

  1. The very cool 7MTT (7-Mode Transition Tool). This is an automation tool we keep rapidly enhancing that dramatically simplifies migrations of complex environments from 7-Mode to cDOT. Any time and effort analysis that ignores how this tool works is quite simply a flawed and incomplete analysis.
  2. After migrating to a new cDOT system, you can take your old 7-Mode gear and convert it to cDOT (another thing that’s impossible with a competitor – you can’t move from, say, a VNX to a VMAX and then convert the VNX to a VMAX).
  3. As of cDOT 8.3.0: We made SnapMirror replication work for all protocols from 7-Mode to cDOT! This is the fundamental way we can easily move over not just the baseline data but also all the snaps, clones etc. Extremely important, and something that moving to a competitor would simply be impossible to carry forward.
  4. As of cDOT 8.3.2 we are allowing something pretty amazing: CFT (Copy Free Transition). Which does exactly what the name suggests: Allows not having to move any data over to cDOT! It’s a combination ONTAP and 7MTT feature, and allows disconnecting the shelves from 7-Mode controllers and re-attaching them to cDOT controllers, and thereby converting even a gigantic system in practically no time. See here for a quick guide, here for a great blog post.
And before I forget…

What about migrating from other vendors to cDOT?

It cuts both ways – anything less would be unfair. Not only is it far easier to move from 7-Mode to cDOT than to a competitor, it’s also easy to move from a competitor to cDOT! Since it’s all about growth, and that’s the only way real growth happens.

As of version 8.3.1 we have what’s called Online Foreign LUN Import (FLI). See link here. It’s all included – no special licenses needed.

With Online FLI we can migrate LUNs from other arrays and maintain maximum uptime during the migration (a cutover is needed at some point of course but that’s quick).

And all this we do without external “helper” gear or special software tools.

In the case of NAS migrations, we have the free and incredibly cool XCP software that can migrate things like high file count environments 25-100x faster than traditional methods. Check it out here.

In summary

I hardly expect to change the minds of people suffering from acute confirmation bias (I wish I could say “you know who you are”, not knowing you are afflicted is the major problem), but hopefully the more level-headed among us should recognize by now that:

  • 7-Mode to cDOT migrations are extremely straightforward in all but the most complex and custom environments
  • Those same complex environments would find it impossible to transparently migrate to anything else anyway
  • Backups/clones is one of those things that complicates migrations for any vendor – ONTAP happens to be used by a lot of customers to handle backups as part of its core value prop
  • NetApp provides extremely powerful tools to help with migrations from 7-Mode to cDOT and from competitors to cDOT (with amazing tools for both SAN and NAS!) that will also handle the backups/clones/archives!
  • The grass isn’t always greener on the other side – The transition from 7-Mode to cDOT is the first time NetApp has asked customers to do anything that major in over 20 years. Other, especially younger, vendors haven’t even seen a truly major code change yet. How will they react to such a thing? NetApp is handling it just fine 🙂


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3 Replies to “7-Mode to Clustered ONTAP Transition”

  1. I can share my experience, which is not the biggest, just a normal customer migration 72C : 26 controllers, 140 volumes, 1 saturday cutover. Yes I’m biased, but it’s a simple fact : 7 to C migration works, and is simple 99% of the time.

  2. Is there a reason why the copy-free 7-Mode to Cluster mode migration requires a purchasing a new controller? Wouldn’t it be possible to purchase a new disk shelf, export the Mode-7 settings, disconnect the controller from the existing 7-mode shelves, connect the existing controller to the new shelf, set up the controller as a new Cluster on the new shelf, connect the 7-mode shelves to the controller, and import the 7-mode settings. Is there a reason why this would not be possible? If so, there still be a way to roll back?

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