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Re: Debian Installation on Ultra 30 (was Re: Updated Debian Ports installation images 2021-09-23)

Hi Hermann,

On 9/27/21 1:56 AM, Hermann.Lauer@uni-heidelberg.de wrote:
> Hi Stan,
> On Sat, Sep 25, 2021 at 11:34:59PM -0600, Stan Johnson wrote:
>> Not knowing what the preferred size should be for a GRUB /boot
>> partition, I decided to let Guided Partioning use its defaults for
>> /dev/sda. As I recall, the partitioner warned that the number of
>> cylinders on the disk exceeded the maximum of 65536, but the creation of
>> filesystems and the rest of the installation proceeded anyway, without
>> any other noticeable errors.
>> The layout for /dev/sda is as follows:
>> # fdisk -l /dev/sda
>> Disk /dev/sda: 136.73 GiB, 146815737856 bytes, 286749488 sectors
>> Disk model: ST3146807LC
>> Geometry: 255 heads, 2 sectors/track, 37965 cylinders
>> Units: sectors of 1 * 512 = 512 bytes
>> Sector size (logical/physical): 512 bytes / 512 bytes
>> I/O size (minimum/optimal): 512 bytes / 512 bytes
>> Disklabel type: sun
>> Device         Start       End   Sectors   Size Id Type         Flags
>> /dev/sda1          0   1000109   1000110 488.3M  1 Boot
>> /dev/sda2    1000110 284748299 283748190 135.3G 83 Linux native
>> /dev/sda3          0 286749029 286749030 136.7G  5 Whole disk
>> /dev/sda4  284748300 286749029   2000730 976.9M 82 Linux swap
> this is a sun disk partitioning scheme - not shure, if this is well supported
> with grub.

Having the above partitioning scheme seems to work ok with GRUB; the
reason I asked about the "Whole disk" partition is that some
partitioning tools (specifically fdisk, as I recall), refuse to create
additional partitions once "Whole disk" has claimed all of the sectors. 
In addition, there is an oddity (I think with parted, but I don't recall
now) where the "Whole disk" partition needed to exist, otherwise the
partitioner only recognized 1 GB. Perhaps this is related to parted
complaining during installation that the number of cylinders on the disk
exceeded the maximum of 65536 cylinders? Maybe parted is reading the
disk geometry from the third partition on the disk regardless of what's

So I ended up using this partitioning scheme; note that parted complains
(but fdisk does not):

# parted /dev/sda
GNU Parted 3.4
Using /dev/sda
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) print                                                           
Warning: The disk CHS geometry (562253,255,2) reported by the operating
system does not match the geometry stored on the disk label
Ignore/Cancel? C                                                         
Model: SEAGATE ST3146807LC (scsi)
Disk /dev/sda: 147GB
Sector size (logical/physical): 512B/512B
Partition Table: unknown
Disk Flags:
(parted) quit

# fdisk -l /dev/sda
Disk /dev/sda: 136.73 GiB, 146815737856 bytes, 286749488 sectors
Disk model: ST3146807LC    
Geometry: 255 heads, 63 sectors/track, 17849 cylinders
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: sun

Device        Start       End   Sectors   Size Id Type         Flags
/dev/sda1         0   1048575   1048576   512M  1 Boot        
/dev/sda2   1060290  17837505  16777216     8G 83 Linux native
/dev/sda3  17848215  34625430  16777216     8G 83 Linux native
/dev/sda4  34636140  68190571  33554432    16G 83 Linux native
/dev/sda5  68195925  70293076   2097152     1G 82 Linux swap      u
/dev/sda6  70300440 286744184 216443745 103.2G 83 Linux native

>> -> Question 1: If I don't plan to install Solaris, is it safe to remove
>> the "Whole disk" partition (/dev/sda3)?
> AFAIR sun disklabels allows up to 8 entries - so there is no advantage in
> removing the solaris standard whole disk entry.
>> -> Question 2: What is the best size for /boot (/dev/sda1)? After
>> installation, the /boot partition had only about 57 MB of files.
> What's on this partition? Only Grub files or also the kernel stuff?
> AFAIR I used around 100-200MB years ago, but this was with SILO.

My experience is mostly with m68k and powerpc Macs, so please excuse my
lack of Sun Sparc knowledge. I recall from many years ago that there is
a "bootblk" on Sparc systems. I learned this after finally reading the
manual when a full restore of Solaris on a new disk failed to boot
because the bootblk was missing.

It appears that SILO and GRUB do something similar -- they appear to be
installed in the 1024-byte "boot block" of an ext2 filesystem; for more
information, see this link for ext2 filesystem structure:


At appears that at least SILO wants the "Boot" partition to be ext2.
These are the only files that I have in my "Boot" partition:

# ls -l
total 172
lrwxrwxrwx 1 root root     1 Oct 22  2020 boot -> .
lrwxrwxrwx 1 root root     1 Oct 22  2020 etc -> .
-rw-r--r-- 1 root root  1024 Aug 19  2012 fd.b
-rw-r--r-- 1 root root   512 Aug 19  2012 first.b
-rw-r--r-- 1 root root  1024 Aug 19  2012 generic.b
-rw-r--r-- 1 root root   692 Aug 19  2012 ieee32.b
-rw-r--r-- 1 root root  7040 Aug 19  2012 isofs.b
drwx------ 2 root root 16384 Sep 26 16:26 lost+found
-rw-r--r-- 1 root root  7680 Oct 22  2020 old.b
-rw-r--r-- 1 root root 53248 Oct 24  2020 second.b
-rw-r--r-- 1 root root   525 Sep 26 16:36 silo.conf
-rw-r--r-- 1 root root   473 Oct 24  2020 silo.conf.save
-rw-r--r-- 1 root root 50994 Aug 19  2012 silotftp.b
-rw-r--r-- 1 root root   512 Aug 19  2012 ultra.b

The Boot partition does NOT have to be mounted as /boot, though it can
be.  Here's my silo.conf file:

# cat /mnt/boot/silo.conf





The advantage to not mounting the Boot partition as /boot is that any
given OS will boot using SILO as long as I create the appropriate
symbolic links for /boot/vmlinuz and /boot/initrd (or I can hardcode the
names as I did above for Debian 7). And according to the silo man page,
silo.conf can be changed at any time using a regular text editor, and
SILO doesn't need to be re-installed after changes. If typos cause the
system to fail to boot, just use rescue mode on any installation CD to
fix silo.conf. I keep Debian 7 so I can re-install the SILO boot block
if necessary (for example on a new disk).


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