> g: 288155687 32017369 4.2BSD 1024 8192 16
>
> I can write this label fine, and a 'newfs /dev/rwd1f' works. However, when I
> do a 'newfs /dev/rwd1g' I get:
>   With 17867 cylinder groups 35 cylinder group summary area are needed.
>   Only 31 are available, reduce the number of cylinder groups
>
> Do you know why this doesn't work?
>

exactly as explained - it's far too much groups to find space for summary.

use

newfs -m 5 -b 8192 -f 1024 -c 64 -i xxx /dev/partition

where xxx are data bytes/inode. default 4096 is far too much unless you
really need to store >10 milions of files. i use 32768 (it must be power
of 2) for every large drive where large is >=10GB. 16384 should be OK too,
less are just waste and eons of fsck'ing

/dev/wd0a    19407477  6472454 11964649    35%  227459  405499    35%   /


using larger block size may give a little speedup (but really difficult to
observe) but waste more space.