Restoring user accounts on new machine, source machine had separate drive for /Users

[mld1]

My fstab looked nearly the same:
yours:
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx /Users hfs rw,auto 0 2
mine:
UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx /Users hfs rw

Maybe they only enforced the selection of options auto or noauto?
It's been a while since my FreeBSD days, what do the 0 2 mean? I have forgotten. They are not in the Yosemite man page for fstab:

blah, blah
EXAMPLES
UUID=DF000C7E-AE0C-3B15-B730-DFD2EF15CB91 /export hfs ro
UUID=FAB060E9-79F7-33FF-BE85-E1D3ABD3EDEA none hfs rw,noauto
LABEL=The\040Volume\040Name\040Is\040This none msdos ro
blah, blah

All I can say for certain is that the fstab worked for Mavericks and for a while on Yosemite, then quit working. Maybe I messed up the permissions somehow? But I used Disk Utility to fix permissions when trying to debug this behavior.

 

[nobodynose]

Here's the link to the 10.9 (Mavericks) version of the fstab(5) man page:
https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man5/fstab.5.html

I am at work so I don't have access to El Capitan man pages, but I SERIOUSLY doubt this man page has changed.

The 5th and 6th fields (the "0" and "2") are the dump frequency and fsck order, respectively. If these fields are missing, their values are assumed to be 0 and therefore neither dump nor fsck is performed. I don't know if these two values even have any meaning anymore in OS X; I think they're just BSD holdovers.

I honestly think the problem you were having was because you were missing the "auto" option; the man page says:

The option "auto" can be used in the "noauto" form to cause a file system not to be
mounted automatically (with "mount -a", or system boot time).

Therefore, your /Users partition wasn't being mounted from its fstab entry at boot time. Instead, it was being mounted automatically by a different process at login time; i.e. the same process that mounts, for example, removable drives when they are plugged into a USB port. Those always appear under /Volumes.

 

[mld1]

Superficial examination suggests the Mavericks and Yosemite man pages are the same.

I think you are correct. I recovered my Mavericks fstab from backup, and I did have auto as an option. I am guessing I had it there in the initial Yosemite build, then recreated it (leaving out auto) during my attempts to recover my user accounts. In any case, I'll never know for sure.

I'm just tired of dealing with this issue for now. I have the Yosemite install working exactly like I want it except for it being entirely contained on the rotational drive. I have deactivated the GRYPHON motherboard build described in my signature (I will be fixing that "Real Soon Now" ). I'll try the separate /Users method again when I bring it back up.