bsdlabel question..

[Gary W. Swearingen]

Glenn Dawson <glenn at antimatter.net> writes:

>                  pp->p_fstype = FS_BSDFFS;
>                  pp->p_fsize = sblock.fs_fsize;
>                  pp->p_frag = sblock.fs_frag;
>                  pp->p_cpg = sblock.fs_fpg;
>          }
> The last line is the one that inserts that number.  sblock.fs_fpg is the number of frags per cylinder grounp.

Glenn, can you tell me which of those numbers, if any, can be changed
after a newfs has been done and the file system well occupied with
data?

(The lousy sysinstall disk labeler wiped out several of my disk labels
and I restored them with zeroes in those fields of the disk label.  It
worked OK, but I'm guessing it only worked because the "bsdlabel"
defaults were the same as they were when I first did "bsdlabel...;
newfs...".  If defaults had changed or I used non-default values the
first time, I'd have been SOL, right?  Or do those values just serve
as optimization/tuning values for the kernel?)