Mailinglist Archive: opensuse (1503 mails)

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Re: [opensuse] Partitioning problem in installing oS v11.1
  • From: Felix Miata <mrmazda@xxxxxxxxxxxxx>
  • Date: Fri, 02 Oct 2009 16:35:25 -0400
  • Message-id: <4AC6640D.90504@xxxxxxxxxxxxx>
On 2009/10/02 19:59 (GMT+0200) Stan Goodman composed:

I hesitat to even look to find out. How can sda4 be even close to the last
cylinder, when sda5, 6, and 7 are near the beginning.

jdd answered this, but as his answer wasn't clear to me, I think it likely
that it wasn't clear to you. Thus, this reply.

To Linux fdisk, the partitions specified in the MBR table are always 1-4. The
names 1-4 are applied to physical partitions in the order that they appear in
the table, which isn't necessarily the same order that they appear on disk.
After partitioning and repartitioning and repartitioning yet again, it's
easily possible for the table entries to bear no relationship whatsoever to
physical disk positions.

When you partitioned with DFSee, you created:

sda1 IBM BM
(sda2 extended)
sda5 swap
sda6 /
sda7 /home

These were contiguous on disk, even though sda2, sda3 & sda4 didn't appear to
exist. What did exist was freespace beyond sda7. In the MBR table, the BM
primary occupied the first table entry. In the second table entry was the
first link in the extended chain (sda2). The 3rd & 4th table positions were
unoccupied.

The oS installer proposed a scheme in which two primary partitions would be
created in the freespace beyond sda7. The only primary entries available were
3 & 4, so that's what the two new partitions would become, even though at the
physical opposite end of the disk from BM and with 3 logicals in between. It
could have made them logicals instead, and been named sda8 & sda9. Either
way, as sda3/4 or sda8/9, they would have occupied the same physical space.

The proposal would have created this result:
sda1 IBM BM
(sda2 extended)
sda5 swap
sda6 (/, but unknown to automatic partitioner)
sda7 (/home, but unknown to automatic partitioner)
sda3 /
sda4 /home

Had you with DFSee created the installer-proposed layout in advance, the
names probably would have come out differently. If you had done:

BM
primary for Linux at end of disk (proposed /)
primary for Linux at end of freespace (proposed /home)
(extended)
logical at start of freespace (swap)
logical at start of freespace (to the installer, unknown)
logical at start of freespace (to the installer, unknown)

the resulting names would have been:

sda1 BM
sda2 proposed /home
sda3 proposed /
sda4 extended
sda5 swap
sda6 unknown to the installer
sda7 unknown to the installer

This is because DFSee would have used the free table slots as it came to
them, 1-4 in order. The end result is still primary partitions on both ends
of the extended, but instead of the extended being named sda2 it gets the
name sda4, as it got the last available MBR table slot.

To really confuse things in the interest of future clarity, you could use
DFSee to very quickly rearrange (sort) the table, changing it from:

sda1 IBM BM
(sda2 extended)
sda5 swap
sda6 (/, but unknown to automatic partitioner)
sda7 (/home, but unknown to automatic partitioner)
sda3 /
sda4 /home

to:

sda1 IBM BM
sda2 /
sda3 /home
(sda4 extended)
sda5 swap
sda6 (/, but unknown to automatic partitioner)
sda7 (/home, but unknown to automatic partitioner)

The partitions themselves, and thus their positions on disk, would not be
touched.


When you partition in advance, you are, to the installation program, an
"expert". Thus to use the partitions you created in advance as you wish, you
must choose the advanced/expert mode of partitioning during installation. In
advanced partitioning, after you have fully partitioned in advance, you only
choose mount points, mount options, and boot loader location; you don't
create or delete partitions, or let the installer guess what you would like
it to do.
--
" A patriot without religion . . . is as great a
paradox, as an honest man without the fear of God. . . .
2nd U.S. President, John Adams
Team OS/2 ** Reg. Linux User #211409

Felix Miata *** http://fm.no-ip.com/
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