Nesting gvinum?

[Rick C. Petty]

On Wed, May 09, 2007 at 11:22:11AM -0500, Jonathan Dobbie wrote:
> Rick C. Petty wrote:
> >
> > Except for the nesting, this is precisely what gvinum does.  Why do you
> > need nesting?  Resizing volumes is something gvinum is supposed to be able
> > to do.
> >   
> I thought that it could only resize striped volumes?  Would you happen
> to have a guide handy?  If I, say, wanted to resize usr and log to add
> 20GB to log, could I drop the s0 subdisk from both, resize, readd, sync
> and then repeat for s1 and s2?

I'm pretty sure you can.  If not, Ulf (lulf@) is working on improvements
this summer.  Now, you weren't expecting to be able to resize the
filesystem automatically, were you?  If so, I think growfs(1) might work.

What I've done with gvinum is move around and "resize" volumes while the
system is up.  By "resize" I mean I always do a copy to a new volume, then
delete the old volume.  I'm not sure if gvinum has a "resize" command,
although IIRC the plain vinum did.

> > UFS2.  It's incredibly fast, even with RAID5 underneath.
> >
> I used newfs and sysinstall to create all of the partitions, so they
> should be UFS2, no?

If you did a newfs or usied sysinstall from 5.x or later, yes.  Read the
"-O" option to newfs(8).

> > I wasn't aware that FreeBSD supported reiser.
> >   
> I was a but surprised as well.
> 
> *HISTORY* <http://www.freebsd.org/cgi/man.cgi?query=mount_reiserfs&apropos=0&sektion=0&manpath=FreeBSD+6.2-RELEASE&format=html#end>
>      The *mount*/_/*reiserfs* utility first appeared in FreeBSD 6.0.

Well what do you know...  scary!

> > Not really.  Software RAID has been proven to be faster than hardware
> > numerous times.  I read somewhere that this has to do with the transfer
> > blocksize or something.  I haven't witnessed this myself, but I've seen
> > gstripe & gmirror outperform RAID0/1 cards.
> >   
> I'm definitely sold on software RAID for 0 and 1, but it is nice to boot
> off of RAID 5 and forget that it is there until a drive dies.

And you can do this with software RAID5 as well.  But I understand your
argument-- sacrifice speed, flexibility, and price to let the card do all
the work.  But also, it matters where you decide to put your trust-- some
company who made a custom ASIC where I can't view or change the code versus
well-written, documented, opensource software...  Sure, gvinum has a ways
to go to support all the old vinum commands, but it's saved me on a number
of occasions already.

-- Rick C. Petty