[comp.unix.ultrix] Redoing Second RZ55 on 3100

jls2@spdcc.COM (Jeff Stoner) (03/12/90)

I have two RZ55's on a DECstation 3100. While mucking around with
the system commands, I noticed that my two drives have the same configuration
(using CHPT -Q command):

partition	bottom		top
  a		     0		 32767
  b		 32768		163839
  g		163840		649039

On the first drive (/dev/rz1* devices), the b partition is used for swapping,
apparently. However, serious sifting through the manuals seems to indicate
that the second drive's b partition isn't being used (this makes sense).

So, I would like to recover that space to make a new filesystem for use
for files (that's alot of disk space missing!). This is where the manuals
get clear as mud. My impression is that the following command would do
it, but I'm not willing to try it until someone else says "yeah, that's
it" (can *you* say "Jeff, Dead Systems Administrator"...? I knew you could...).

newfs -v -n /dev/rrz3b rz55

Or am I way off? Thanks for any help you can give...

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grr@cbmvax.commodore.com (George Robbins) (03/12/90)

In article <2054@ursa-major.SPDCC.COM> jls2@ursa-major.spdcc.COM (Jeff Stoner) writes:
> I have two RZ55's on a DECstation 3100. While mucking around with
> the system commands, I noticed that my two drives have the same configuration
> (using CHPT -Q command):
...
> On the first drive (/dev/rz1* devices), the b partition is used for swapping,
> apparently. However, serious sifting through the manuals seems to indicate
> that the second drive's b partition isn't being used (this makes sense).
> 
> So, I would like to recover that space to make a new filesystem for use
> for files (that's alot of disk space missing!). This is where the manuals
> get clear as mud. My impression is that the following command would do
> it, but I'm not willing to try it until someone else says...
> 
> newfs -v -n /dev/rrz3b rz55

Yeah, that's pretty much the story.  The swap area on the second drive is
only used if it's both in the config file and in /etc/fstab as a swap area.

You should give some thought to whether or not you want to have a secondary
swap area.  It isn't too hard to use it all up and there may be some performance
gain from having two areas.

The newfs command will do the trick as long as all the parameters for the
partition on that kind of drive are present in /etc/disktab.  Some of the
older ones were missing blocksize but I think the newer disks are complete.

You have the option of making a small 'b' filesystem or instead using the
'c' filesystem which traditionally maps the who disk...

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)

mao@eden (Mike Olson) (03/17/90)

In article <10114@cbmvax.commodore.com>, grr@cbmvax.commodore.com
(George Robbins) writes:
> In article <2054@ursa-major.SPDCC.COM> jls2@ursa-major.spdcc.COM
(Jeff Stoner) writes:
>> I have two RZ55's on a DECstation 3100. While mucking around with
>> the system commands, I noticed that my two drives have the same
>> configuration ...
>> newfs -v -n /dev/rrz3b rz55
> You should give some thought to whether or not you want to have a secondary
> swap area.

you may also want to reserve this as swap space, so that you can boot off
the second drive if the first dies.  this would be uncomfortable if there
were a file system on the b partition.

					mike olson
					postgres research group
					uc berkeley
					mao@postgres.Berkeley.EDU

meissner@osf.org (Michael Meissner) (03/17/90)

In article <23119@pasteur.Berkeley.EDU> mao@eden (Mike Olson) writes:

| In article <10114@cbmvax.commodore.com>, grr@cbmvax.commodore.com
| (George Robbins) writes:
| > In article <2054@ursa-major.SPDCC.COM> jls2@ursa-major.spdcc.COM
| (Jeff Stoner) writes:
| >> I have two RZ55's on a DECstation 3100. While mucking around with
| >> the system commands, I noticed that my two drives have the same
| >> configuration ...
| >> newfs -v -n /dev/rrz3b rz55
| > You should give some thought to whether or not you want to have a secondary
| > swap area.
| 
| you may also want to reserve this as swap space, so that you can boot off
| the second drive if the first dies.  this would be uncomfortable if there
| were a file system on the b partition.

One thing I did once when mananging a UNIX system was to put /tmp on
the secondary filesystem where swap went on the first disk and just do
mkfs before mounting it.  That way you don't waste disk space (if disk
space is tight), but you can still boot off of a secondary disk if
problems come up.
--
Michael Meissner	email: meissner@osf.org		phone: 617-621-8861
Open Software Foundation, 11 Cambridge Center, Cambridge, MA

Catproof is an oxymoron, Childproof is nearly so