Re: Disk Structures

Are you using the official Raspberry Pi images or imager?  I believe there’s a few specific requirements for the partitions...

> On Dec 13, 2025, at 4:54 PM, Doug Hardie <bc979@lafn.org> wrote:
> 
> I have a couple of Raspberry Pi 5s.  One of which is a production server for mail.  It works just fine.  However, the disk structure is quite confusing.  I only noticed this because of trying to bring up another similar server.  
> 
> If I list the dev entries for mmcsd, I get the following.
> 
> mail# ll /dev/mmcs*
> crw-r-----  1 root operator 0x49 Nov 26 15:47 /dev/mmcsd0
> crw-r-----  1 root operator 0x4a Nov 26 15:47 /dev/mmcsd0s1
> crw-r-----  1 root operator 0x4b Nov 26 15:47 /dev/mmcsd0s2
> crw-r-----  1 root operator 0x4e Nov 26 15:47 /dev/mmcsd0s2a
> crw-r-----  1 root operator 0x4f Nov 26 15:47 /dev/mmcsd0s2b
> 
> This looks like the drive was partitioned using GPT.  However, gpart list shows MBR.  I removed the non-relevant entries:
> 
> mail# gpart list mmcsd0
> Geom name: mmcsd0
> entries: 4
> scheme: MBR
> Providers:
> 1. Name: mmcsd0s1
>   Mediasize: 52428800 (50M)
>   type: fat32lba
> 2. Name: mmcsd0s2
>   Mediasize: 128124452864 (119G)
>   type: freebsd
> 
> There are the two partitions I expected.  A boot partition, and a data partition.  Looking at the df output:
> 
> mail# df -h
> Filesystem          Size    Used   Avail Capacity  Mounted on
> /dev/ufs/rootfs     108G    9.1G     90G     9%    /
> devfs               1.0K      0B    1.0K     0%    /dev
> /dev/msdosfs/EFI     50M     25M     25M    50%    /boot/efi
> tmpfs                12G     85M     12G     1%    /tmp
> /dev/da0s2           25G    1.3G     22G     6%    /mailbkup
> mail# 
> 
> The entries for / and /boot/efi are not at all what I expected.  The /mailbkup seems normal.  How do I make sense of all this?
> 
> I duplicated the microSD card but it doesn't boot the new machine.  I believe that is caused by a hardware failure in the Pi.  It does some strange rebooting before ever reading the SD card.  Never the less, I should be able to mount the copied SD card on a working machine, but can't figure out how to do that.  Messages shows the new disk is da1.
> 
> mail# mount /dev/da1s2 /mnt
> mount: /dev/da1s2: No such file or directory
> mail# mount /dev/mmcsd1s2b /mnt
> mount: /dev/mmcsd1s2b: No such file or directory
> 
> I would like to verify that the new SD card is good.
> 
> 
> -- Doug
> 
>