Adventures in cMode Migrations: Part One

By April 1, 2014NetApp, Storage

On paper, a 7-Mode to the Clustered Data OnTap (“cDOT”) migration can seem fairly straightforward. In this series, I will discuss some scenarios in terms of what can be very easy vs. what can be extremely difficult. (By “difficult” I’m mostly referring to logistical and replication challenges that arise in large enterprise environments.)

The Easy First!

Tech refresh in one site:

Bob from XYZ corp is refreshing his 7-Mode system and has decided to take advantage of the seamless scalability, non-disruptive operations and the proven efficiencies of 7-Mode by moving to the cDOT platform. Hurray Bob! Your IT director is going to double your bonus this year because of the new uptime standard you’re going to deliver to the business.

Bob doesn’t use Snapmirror today because he only has one site and does NDMP dumps to his tape library via Symantec’s Replication Director. Plus 10 points to Bob. Managing snapshot backups without a catalogue can be tricky. Which Daily.0 do I pick? Yikes! Especially if he gets hit by a bus and the new admin has to restore the CEO’s latest PowerPoint file because Jenny in accounting opened up a strange email from a Nigerian prince asking for financial assistance. Bad move, Jenny! Viruses tank productivity.

Anyway …

Bob’s got a pair of shiny new FAS8040s in a switchless cluster, the pride of the NetApp’s new mid-range fleet. He’s ready to begin the journey that is cDOT. Bob’s running NFS in his VMware environment, running CIFS for his file shares and about 20 iSCSI LUNs for his SQL DBA. Bob also has 10G switching and servers from one of the big OEMs. So no converged network yet, but he’ll get there with next year’s budget with all of the money he’s going to save the business with the lack of downtime this year! Thanks cDOT.


So what’s the plan of attack? After the new system is up and running, from a high level it would look something like this.

1. Analyze the Storage environment

a. Detail volume and LUN sizes (excel spreadsheets work well for this)
b. Lay out a migration schedule
c. Consult the NetApp Interoperability Matrix to check Fiber channel switch, HBA firmware and host operating system compatibility.
d. Build the corresponding volumes on the new cDOT system
e. Install the 7-Mode migration tool on a Windows 2008 host.
f. Using the tool to move all file based volumes.

That wasn’t so hard. Actually on paper, it looks like this scenario may seem somewhat trivial but I can assure you it is this straightforward. Next time, we are going to crank up the difficulty level a bit. We will add in multiple sites, a Solaris (or insert any other esoteric block OS, HPUX anyone?) environment as well as the usual NAS-based subjects.

See you next time for Part Two.

Photo credit: thompsonrivers via Flickr