Hello!

On 9/26/21 07:34, 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
> 
> -> Question 1: If I don't plan to install Solaris, is it safe to remove
> the "Whole disk" partition (/dev/sda3)?

I think so.

> -> Question 2: What is the best size for /boot (/dev/sda1)? After
> installation, the /boot partition had only about 57 MB of files.

It should be at least 150 MB as you can easily run out of disk space
there when multiple kernels are installed. You can also live with 100 MB
or less, but then you always need to make sure to purge old kernels
before installing a new one.

I have often run into the situation that I ran out of disk space when
/boot was small, so we eventually decided to raise the minimum size
for automatic partitioning.

> After installation, at every boot, I see this:
> -----
> GRUB Loading kernel....
> Welcome to GRUB!
> 
> error: out of memory.
> error: no suitable video mode found.
> error: no video mode activated.
> -----

There are some limitations with GRUB on older machines, unfortunately.

> Then the GRUB menu is displayed, and I am able to scroll through the
> options using the "v" and "^" keys (but not the up and down arrow keys).

I think that applies to all systems which basically use a (virtual) serial
console where arrow keys aren't necessarily available.

> After selecting the new Debian SID (or allowing it to be selected by
> default), the X login eventually comes up, but it seems to be off the
> screen. If I login anyway, the Xfce desktop comes up, but it seems to be
> larger than the screen. This problem, which is similar to a problem I
> had with Debian 7.8, can probably be fixed with an appropriate xorg.conf
> file.
> But UUID=052feb55-ef72-4a8a-8f6d-2d63390e76ff doesn't exist.
> 
> So this line:
> 
> linux /boot/vmlinux-5.14.0-1-sparc64
> root=UUID=052feb55-ef72-4a8a-8f6d-2d63390e76ff ro quiet
> 
> should be:
> 
> linux /boot/vmlinux-5.14.0-1-sparc64
> root=UUID=1ca6137b-dcb8-4e76-b3c5-794d453723ca ro quiet
> 
> as shown by blkid:
> 
> # blkid /dev/sdb1
> /dev/sdb1: UUID="1ca6137b-dcb8-4e76-b3c5-794d453723ca" BLOCK_SIZE="4096"
> TYPE="ext3" PTTYPE="sun"
> 
> After making that change, I'm able to boot into my backup Debian SID
> installation.

Might be an issue with os-prober that is part of GRUB.

> So my choices at this point are to return to SILO or follow through with
> a bug report for GRUB (I would need help submitting upstream bug reports
> for GRUB).

Bear in mind that SILO is basically dead upstream and might have issue with
certain filesystems used for /boot.

> -> Question 3: If I return to SILO, is there anything special about
> /dev/sda1 other than it needing to be ext2? For example, are there any
> special flags or other attributes needed for that partition? Is
> /dev/sda1 also ext2 when using GRUB or can it be ext3 or ext4?

The point with /boot being small and using an older, simpler filesystem is
because the bootloader accesses the kernel and initrd files using blocklists,
i.e. by ignoring the actual filesystem.

If you have a filesystem with a complicated on-disk format, both GRUB and
SILO might have trouble finding the blocks of kernel and initrd and loading
them.

So, for the sake of compatibility, I recommend not using anything newer than
ext3 for /boot.

Adrian

-- 
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer - glaub...@debian.org
`. `'   Freie Universitaet Berlin - glaub...@physik.fu-berlin.de
  `-    GPG: 62FF 8A75 84E0 2956 9546  0006 7426 3B37 F5B5 F913

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