One of the nice things about my role at NetApp is a lot of freedom to pursue projects I think will help advance our presence in the enterprise application and database space. About 25% of my time is linked to specific requests from management, but the rest of my time is discretionary.
When I was writing the Oracle migration document mentioned in a previous post, I decided to take a closer look at a newer feature called “Foreign LUN Import”. I requisitioned a mixed SAN environment (thanks Graham!) and started experimenting.
I just wanted to see the process at first, but it was compelling enough that I decided to repeat the procedures and capture the output with Camtasia. This is the result:
If you haven’t heard of it, FLI is basically a way for an ONTAP array to import the contents of another array. With a little preparation work, you can move the contents of your SAN to ONTAP with just a few minutes disruption.
This is essentially how it works:
- Zone the new ONTAP array to the legacy array.
- Decide which LUNs you want to transfer.
- ONTAP will then read the configuration of those LUNs. It’s not moving any data yet, it’s just contructing new LUNs based on the current configuration.
- At this stage, ONTAP is now able to work as a proxy for the legacy array LUNs.
- Now you’re ready for cutover. Shut down the servers and change the FC zones to point to the ONTAP LUNs.
- Start up the hosts again and check connectivity. On occasion, the change in WWNs might require a corresponding change to host configuration, but hosts using a volume manager should transparently adjust to the changes.
- If everything looks good, initiate the data transfer. This is a large-block sequential IO operation which runs quickly and shouldn’t affect performance.
- Once the transfer is complete, remove the old array.
It’s also worth mentioning I did this with zero experience with this feature, zero training, and no assistance from anybody. I did the entire process remotely. I’ve never even seen the lab gear. I just logged into the hosts and the FC switch, figured out the plumbing, and ran some commands.
Worked like a charm. If you need to upgrade your FC SAN, this probably should be the default migration option.
Update: I forgot to mention – when you migrate you also get all the storage efficiency benefits of ONTAP. Inbound data will be compressed, compacted, and/or deduplicated based on however you’ve configured the array.