vmware vcenter appliance 5.0.0 update slow

First, while it would be amazing to get a solution, at this point I'm willing to accept new ideas to try.

Here is the background:

What I'm trying to accomplish is to upgrade an old vCenter Appliance 5.0.0 to at least 5.5. I've tried all kinds of things, but every time the upgrade fails with red X beside "upgrading vcenter appliance"

This is what I've tried

• Tried upgrading from 5.0 -> 5.1 (fails same way)
• Tried upgrading from 5.0 -> 5.5 (fails same way)

My latest goal is to update from from 5.0.0.3324 build 472350 -> 5.0.0.latest. It looks like the version I'm running is DB2 and I wonder if the transition from DB2->postgres->new version is just too much. That's why I thought I'd give it this easier task. This task never fails. Instead it runs for a week crunching away at /storage/db/export/*.lob files. I looked into some of them randomly and all 5 that I looked at contain the word "en". I'm wondering if it went into some kind of a loop. There was 7 million+ of them there in total. I didn't have the patience for it to finish, because right now I'm doing the upgrade in the lab, and even if it did finish, it would not be viable solution for the live environment. I can't be without vcenter for a week. I tried pruning the database size by turning off logging and reducing retention. That didn't seem to make a difference. Is there a way to prune this so that the update doesn't take more than 1 day?

Now thinking outside of the box:

• Let's say I give up on automatic update and upgrade, what's the best way to get my configuration manually imported from the old environment? I saw an option where I could import config. But how do I export?
• Let's say that I even give up on export/import and I just rebuild from scratch. Are there any guides that walk me through the process of doing that?
• Are there other things I should try with the upgrade before giving up on it or am I at a dead end?

Thank you