I just did a 22.5million post import from vb3.8 to xen1.1. (still sorting it all out) I emptied all of the search related tables before I even tried mainly to make my backup a little smaller. I wasn't aware of the command line installer till just now so I used the normal importer. I told it to retain the IDs for redirect reasons. xenforo went very smoothly including attachments. all my issues were my issues & not xen.
when the importer got to the posts & threads step, it ran for a couple days. I think it was 80hrs but to be fair, it would stop in the middle of the night & I wouldn't get it going again till the next day. several times i had generic errors saying it stopped but hitting the continue button (or refresh or back button) got her going again. i assume these were time-outs or net connection issues. at one point I got serious error "Duplicate entry '14094910' for key 1" and there was no continuing after that. I was out of town too trying to fix it from an ipad in a hotel room. i tried a million things and thought for sure I was doomed. then I found the issue. the server logs had filled the hard drive. (it was more than half the drive) not knowing how to telnet from an ipad I called the host & had them delete the logs for me. I had a friend in the office go back & refresh the page. xen started back up & kept on going. believe it or not my computer did a windows update & automatically restarted in the middle of the night while the import was still going. in pain I started her back up in the morning, opened firefox & clicked the "open previous session link". it brought me to the ACP login screen and after logging in I **** you not, the import just picked up where it left off. when it finished I couldn't have been more impressed w/ xenforo.
the import finished & I started looking around. everything seemed to be there. the counts in the different forums seemed correct. the total post count in the stats seemed correct. looking at the database from phpmyadmin however was alarming. the post table size had doubled from 6GB to 12GB & the post count was down from 22 million to 11. I had no idea what had happened but was confident all my restarts were the culprit. I did the import again, went thru the whole rigamerall & got very similar results. Here on the board Mike told me not to worry about the numbers I see on phpmyadmin because it's an InnoDB thing. (
LINK) I nervously accepted that and you know what? I just looked now (after being back open for a week or 2) & phpmyadmin thinks I have 24.5million posts now even though it still says 12GB so I guess he knew what he was talking about. it's still not the right count i'm a lot less worried that 11 million posts disappeared.
rebuilding all the cache stuff took another day or so. I did NOT attempt to do the search index. the big board search will be avail in a week or two so my people can settle for only searching new posts for now.
as for custom fields, they all imported. so did PMs to conversations, & even ban records. I got the user albums to import using a 3rd party importer & addon.
what didn't import were the subscriptions. nothing about them or the donations moved over. worse than that, I had month to month automatically recurring payments setup & paypal was still recurring them thought he vb board was off & moved. I had to log into paypal & manually cancel all the subscriptions. i'm working on getting all that straightened out now. I tried adapting the v4 importer but once I realized the recurring payments weren't going to work no matter what I did I said screw it.
usergroups are a little odd. xen handles them differently w/ a main "registered" group & then addon upgrade groups. the imported accounts wind up w/ people in a main "upgraded" group instead of reg + the upgrade. if you could mass move people between groups it would be less of a big deal but we don't seem to have that power yet. not sure how i'll handle that since i'm told you can't just change the IDs in the DB because you'll wind up w/ permissions screwed up. still, it hasn't been an issue yet.
there doesn't seem to be a way to mass move threads or mass delete them yet. if you are going to re-organize, you may want to do it before the import.
that's about all I can think of right now. good luck. you'll like xen