With the release of vSphere 6.0 U2 and VSAN 6.2 I was eager to upgrade to get the new features of VSAN. I run a 3 node cluster at home with an SSD and magnetic disk in each node. Unfortunately the straight upgrade isn’t as easy as expected due to this, admittedly, bad setup if this wasn’t just a home lab. You will get a similar error:
A general system error occurred: Failed to evacuate data for disk uuid 522de09d-50f0-083a-0cc6-ee47c89787b2 with error: Out of resources to complete the operation
The way around this is to force the upgrade allowing you to enter a much less redundant scenario. I would obviously NOT do this on anything you consider hugely important and instead reevaluate your VSAN configuration to ensure redundancy in this situation. If you do want to go ahead, make sure your backups are current, log into the shell of your VCSA and run the following command replacing the $ variables with your names:
vcenter:~ # rvc firstname.lastname@example.org@localhost
> vsan.v2_ondisk_upgrade /$vcserver/$dc/computers/$cluster
Things should kick off at this point and go through the whole process. You WILL get warnings about VSAN health in the client during this as you are going to be running reduced redundancy and requiring resyncs. Expect this to take a very long time.
Again, do not do this in a situation where data loss matters.