ontap upgrade two major version on the same time

[JohnChen]

My current Ontap version is 9.1P5.

I want to upgrade it to be ontap 9.5P2.

According to upgrade advisor, I need to upgrade it to be 9.3 first.

Therefore, on the same night, I will upgrade ontap from 9.1P5 to 9.3P12 and then 9.5P2.

As I know that, after i upgrade it to 9.3P12, there are several firmware will be update automatically if the version in your cluster is older than the firmware that is bundled with the ONTAP upgrade package.

They are BIOS, Flash Cache, SP, Disk, and Disk shelf.

My question here is 

Do I need to wait for all those firmware upgrade completed and then upgrade it from 9.3P12 to 9.5P2 or I can continue to upgrade it to 9.5P2 after veified the version - 9.3P12 and HA status, aggregate, and lifs are home port?

9.3P12 release on 5/27/2019

9.5P2 release on 3/24/2019 which is earlier then 9.3P12.

Does it matter for my upgrade ? 

[SpindleNinja]

I would pick the latest P releases.   But I would not jump from 9.1 to 9.3 to 9.5 in one day.    When I run through this with customers I typically will wait a week or so between the major updates.     

But to answer your question, yes you will need to wait for all the background firmware updates to finish before moving on.     The disk and shelf firmware could be the same between the two versions,   but SPs and other firmware will be different between 9.3 and 9.5.    

I would also run through the IMT to verify that everything in your environment has compatibility with the new versions of ONTAP.   

[JohnChen]

According to NetApp support, I can continue to upgrade from 9.1 to 9.3 and then 9.3 to 9.5.

I did it with two nodes under the cluster.

After I upgrade from 9.1 to 9.3, I verifyed HA and its related objects and upload autosupport to Active IQ, and run the config advisor.

I see no issue from both and after 30 minutes, then I continue to upgrade it to 9.5.

It runs fine without any issue until today...5 days already...

From the preparation, upgrade, and verification, it took me at least about 3.5 hours for two nodes.

Therefore, if you have nore then two nodes under a cluster, then I will prefer to do it not on the same day.

However, I see no issue to upgrade it for two major versions on the same time. 

[lwebb]

If you have firewalls between some of your lifs, be sure to verify your routes.    Ontap 9.2 had major changes including removal of fastpath, this can really break things.    This really burned me on my upgrade  to 9.3.