Striped Drive for OS File System

Donald E. Holt donald.holt at
Sun Mar 23 23:57:54 UTC 2008

Lee, thanks so much for the great info. I may still bollix things up,
but at least I know that the operation itself isn't doomed from the

The man pages seem to be thorough, so I believe I can work out the
precise steps there. I do have two remaining questions, if I may beg
your patience.

I am able to backup /usr to tape. In light of that fact, would you
recommend gstripe? I should do a bit more research on my own concerning
the differences between gstripe and gconcat prepared drives, I know, but
I'd value your advice.

Second question. The drive that currently contains /usr also has a swap
partition (in addition to the swap partition on the first SCSI drive). I
assume the second swap isn't absolutely necessary, but would it be
worthwhile (or possible) to designate a portion of the concatenated
space to swap?

Thanks again!
On Sun, 2008-03-23 at 19:10 -0400, Lee Dilkie wrote:

> Donald,
> Yes, it can be done but as a gconcat rather than a gstripe if you need 
> to expand in place.
> essentially,
> unmount /usr
> create gconcat from existing /usr and new drive (use raw drive.).
> then use growfs to expand gconcatted drive
> mount gconcatted version of /usr
> If you can do a backup and restore of /usr, you could create a stripped 
> drive instead (if they are the same size or thereabouts).
> The only gotcha that I had was in FreeBSD 5.5. Growfs doesn't handle 
> really big disks (which is what you get here). I found that the patch to 
> fix growfs in 6.2 and manually did it and rebuilt growfs and it worked 
> great. I've done it twice now, adding a third drive to my gconcat array.
> Also. I only used gconcat with the raw drives, ie "gconcat label  
> big_drive /dev/ad2 /dev/ad3 /dev/ad4" but I presume it works the same 
> with slices/partitions.
> -lee
> Donald E. Holt wrote:
> > I haven't seen this particular situation discussed, nor have I been able
> > to find any specific information on the web. I am not experienced in
> > GEOM or vinum, so I may be asking a dumb question. If so, I apologize.
> >
> > My system has FreeBSD installed across 2 SCSI drives. /dev/da2
> > holds /, /tmp, /var, and a swap. /dev/da4 is devoted to /usr and another
> > swap. A third drive (dev/da5) is dedicated to a Win4BSD virtual machine,
> > and is mounted as /WinXP (there are still a few MS apps I can't get
> > around using).
> >
> > I'd like to expand /usr fs to an additional SCSI drive (physically
> > present now, but unused). Would it be possible to do that, perhaps with
> > gstripe, without distroying data on the current drive?
> >
> > Again, sorry if I've asked one of those eye-rolling, forehead-thumping
> > questions.
> >
> > Thanks!
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> >
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