Summary for repartitioning disk drives:
Below I have included my original question and concerns about
repartitioning disk drives for use with DU4.0. Many thanks to those
who responded. I have included the response from Cliff because
his response was very complete and very easy to follow. This is much
better than anything I could summarize. Cliff, again I really appreciate
your help here. Hopefully this will answer some questions for any of
you who may be getting ready to attempt this as well. It really looks
to be pretty simple and straight forward. (famous last words :-)
On Wed, 16 Oct 1996, Darryl Cook wrote:
> 8 partitions:
> # size offset fstype [fsize bsize cpg]
> a: 131072 0 4.2BSD 1024 8192 16 # (Cyl. 0 - 82*)
> b: 389520 131072 unused 1024 8192 # (Cyl. 82*- 328*)
> c: 4110480 0 unused 1024 8192 # (Cyl. 0 - 2594)
> d: 0 0 unused 1024 8192 # (Cyl. 0 - -1)
> e: 0 0 unused 1024 8192 # (Cyl. 0 - -1)
> f: 0 0 unused 1024 8192 # (Cyl. 0 - -1)
> g: 2097152 520592 4.2BSD 1024 8192 16 # (Cyl. 328*- 1652*)
> h: 1492736 2617744 4.2BSD 1024 8192 16 # (Cyl. 1652*- 2594*)
>
>
> My question is this. Partition g is /usr and h is /usr2. I would like to
> just get rid of h (usr2) and redistribute it among partition a,b, and g.
> this would increase the root , swap and usr partitions. I would then set
> the size and offset of partition h to zero, and fstype to unused. Any
> problems with doing this? Would the columns containing the 16 need to be
> modified, I would suppose just blank it out?
>
Cliff wrote:
You realize, of course, that you can not just increase the size of an
existing partition without wiping it out? Presuming that what you really
plan on doing is backing everything up and then changing the sizes, you
would proceed as follows. Start with partition a since it is first on
the disk.
Presuming that you wanted to double the size, you would just
change line a: to look like this:
size offset fstype [fsize bsize cpg]
a: 262142 0 4.2BSD 1024 8192 16
That will give you about 130M for root. Next we will look at swap on
partition b: You currently have about 195M. Lets presume that you
wanted about 350M. Line b: would look like this:
b: 700000 262142 unused 1024 8192
Note two things: First, the offset is now the same as the offset of line
a: plus the size from line a: Second, I have made no attempt to line
this partition up on a cylinder boundery which would give a performance
advantage.
Next, we turn our attention to line g: We will give it the rest of the
space on the disk for this example.
g: 3148338 962142 4.2BSD 1024 8192 16
Note that the size and offset of the last partition on the disk will
equal the total size of the disk when added together...presuming that you
have no unused space.
Note also that you can leave all the fields after size and offset blank
as they will be filled in by the newfs command when you recreate the file
systems. You will have to manually change the h: partition to unused
since there is no unnewfs command.
Note that the * in the comment field on the right indicates when you are
splitting a cylinder. You can incrementally change the size and offset
to get right on the edge, but be carefull that you don't have two
partitions overlap. I think that some drives even spoof some of this
data, so it may not work. I haven't done tests, but my gut reaction is
that the cylinder boundry benefit is somewhat overstated.
-cliff
------------------------------------------------------------------------
Darryl Cook | e-mail -- pgmr_at_ppalf.appstate.edu
Applications Programmer II | phone -- (704)-262-3190 x107
Appalachian State University | fax -- (704)-262-4017
265 Dale Street |
Boone, NC 28608 |
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Received on Thu Oct 17 1996 - 22:29:56 NZDT